A parallelogram is a quadrilateral with two pairs of opposite sides. IV. ... math.stackexchange.com Opposite angles are congruent and the diagonal bisects it. Here’s our regular, non-special parallelogram with the diagonals shown: As you can see, the diagonals of a parallelogram bisect each other. II. (D.) Diagonals are congruent. This means every parallelogram is: A plane figure (it has two dimensions) A closed shape (it has an interior and exterior) A quadrilateral (four-sided plane figure with straight sides) What Does a Parallelogram Look Like? Hello, Can some one check my work. Learn how to solve problems about rectangles. A polygon is a shape with multiple sides. 3) Every rectangle is a square. Some of the important properties of a parallelogram are: Opposite sides are of equal length and are parallel to each other. Take a rectangle and push either its left or ride side so it leans over; you have a parallelogram. Textbook Solutions 4940. False. Remember the tree? See more. If the diagonals of a parallelogram are congruent, then it’s a rectangle and also if a parallelogram contains a right angle, then it’s a rectangle. В. (D.) Diagonals are congruent. A parallelogram which has all sides congruent can be considered as a rhombus.A parallelogram that has all angles at right angles and the diagonals are equal will be considered as a rectangle. ... math.stackexchange.com Every parallelogram is a trapezium IV. Add your answer and earn points. Okay, only one quadrilateral left, the square. The diagonals of a parallelogram bisect each other. The sum of all interior angles is \(360^\circ\). 3) Every rectangle is a square. The diagonals of a parallelogram bisect each other. Parallelogram definition, a quadrilateral having both pairs of opposite sides parallel to each other. Every square is a rectangle----False as square is a rectangle with equal sides but rectangle is not a square. Every rectangle has perpendicular sides. Every parallelogram is a rectangle. 60 seconds . Which property is not true for all parallelograms? It has 4 sides (edges) It has 4 corners (vertices) It has 4 right angles . 2) Every rhombus is not square. This conundrum is due to Vladimir Nikolin, an elementary school teacher from Serbia. Every quadrilateral has perpendicular lines. This means that the diagonals of a rhombus are perpendicular to each other in addition to bisecting each other. The opposite angles of a rhombus are equal. rosariomividaa3 and 229 more users found this answer helpful True. Likewise, for a parallelogram to be a rectangle, it must have all the four interior angles of equal magnitude, i.e., 90 degrees. The rectangle is a special case of a parallelogram in which measures of its every interior angle is 90 degree. IV. Every rhombus is a parallelogram. The opposite sides of a rectangle are parallel and congruent. Maharashtra State Board SSC (English Medium) 9th Standard. Take a rectangle and push either its left or ride side so it leans over; you have a parallelogram. A rectangle is a parallelogram that has four opposite, parallel, congruent sides. Take point H on ray DG such that D-G-H and DG = GH, then prove that `square` GEHF is a parallelogram. A parallelogram with all 4 interior angles congruent to each other is called a rectangle. answer choices . The three special parallelograms — rhombus, rectangle, and square — are so-called because they’re special cases of the parallelogram. True. So, straight from a definition we see that any rectangle is a parallelogram with additional property of having all interior angle congruent to each other. Opposite angles are congruent. In fact, a rectangle is a quadrilateral whose interior angles measure #90^@#.This is one of the two conditions expressed above for a quadrilateral to be a … A diagonal is a line segment connecting opposite vertices, or corners, of a quadrilateral. Which property is not true for all parallelograms? The adjacent sides of a parallelogram be the vectors and . and are diagonal of the parallelogram. We will study the other properties of different quadrilaterals in detail. Q. Every parallelogram is a rectangle. Today we’re going to explore the diagonals of parallelograms, rectangles, rhombi, and squares, and see how these shapes relate to each other overall. or we could use tick marks to show that the diagonals have been bisected: Since the three special quadrilaterals we’re talking about are all parallelograms, they will all have bisecting diagonals. Every rectangle is a quadrilateral. State whether the following statements are true or false. Every square is a rhombus and every rhombus is a parallelogram. State whether the following statements are true or false. Assume parallelogram is a rectangle and its diagonals are equal in length. There are certain criteria that identify a quadrilateral shape as a parallelogram. (1 A rectangle is a parallelogram ) A rhombus is a square (3) A quadrilateral is a trapezoid (4) A trapezoid is a parallelogram 12. Why is a rectangle a parallelogram, but a parallelogram is not a . This video shows several examples of diagonals of parallelograms, specifically rectangles, squares, and rhombi. When playing “Name That Quadrilateral,” your answer must be as general as possible. Because a square is a rectangle but a rectangle need not be a square, the most general quadrilateral that fits this description is a rectangle. A rectangle is a shape we all know well since it appears in the real world so often. A rectangle is often described as a special case of the parallelogram, since it has similar properties but with the height being the same as one of the parallel sides. A parallelogram is a quadrilateral with 2 pair of opposite sides parallel. Characterizations. It has all the properties of the parallelogram but all of the sides of a rhombus are congruent. Like other parallelograms, opposite sides in a rectangle are parallel to each other. Area = 6 m × 3 m = 18 m 2. In the same way, every rectangle is a parallelogram in that it satisfies the conditions to be such a figure: it is a quadrilateral with two pairs of parallel edges. Let denote H(p, q, r) Heron's formula for a triangle with sides p, q, r. Consider triangles ABC and DAB; there sides are a, b, d1 and a, b, d2, respectively. Every square is a parallelogram----- True as square ia parallelogram with sides of equal measure and angles equal to 90°. Perimeter: The perimeter of a rectangle is the sum of the length of its four sides. Not every parallelogram is a rectangle and not every rhombus is a square. False. NOTE: There are different definitions of a rectangle, all equivalent to each other. Every square is a rectangle A parallelogram is a polygon whose opposite sides are parallel. Both the … Rectangle definition, a parallelogram having four right angles. D. Diagonals are congruent. Summary of Parallelogram Vs. Rectangle. Rectangle also have similar properties of parallelograms such as the opposite sides of a rectangle are parallel to each other as parallelogram. Which statement is ALWAYS true? It’s another shape we all know well… the square! 60 seconds . Every rectangle is a parallelogram. Every quadrilateral has parallel sides. Every parallelogram is a rhombus. Practice Set 5.2 | Q 3 | Page 67. A parallelogram is a square. (false) 17. (1) Every parallelogram is a rectangle (2) Every rhombus is a square (3 Every trapezoid is a parallelogram 4 Every square is a rhombus 11. The correct answer is B. A rectangle is a special parallelogram that has 4 right angles. III. Rhombus: A parallelogram with sides of … Learn More... All content on this website is Copyright © 2021. A. A diamond shape is a good example of a rhombus. Now that we’ve got rectangles figured out, let’s see what happens with another special parallelogram, the rhombus: Once again, since every rhombus is a parallelogram the diagonals bisect each other. So I'm thinking of a parallelogram that is both a rectangle and a rhombus. The diagonals of a rhombus intersect at right angles. III. The answer is yes. With the same argument one proves that #BC# and #AD# lie on parallel lines, and this proves that every rectangle is a parallelogram. Why is a rectangle a parallelogram, but a parallelogram is not a . False. A parallelogram is a quadrilateral that has two sets of parallel sides. It is a parallelogram with four identical sides and diagonals that bisect at a right angle. Every rhombus has perpendicular sides. Diagonals of a parallelogram bisect each other. False. Your question as phrased is wrong. Properties of parallelogram: Opposite sides are congruent; Opposite angles are congruent; consecutive angles are supplementary,i.e. SURVEY . A parallelogram where all angles are right angles is a rectangle! That’s how it works going up the tree. Here’s our regular, non-special parallelogram with the diagonals shown: As you can see, the diagonals of a parallelogram bisect each other. A. I. False 3) Every rectangle is a square. Explanation; -A parallelogram is a quadrilateral with 2 pairs of opposite, equal and parallel sides. Opposite sides are equal. A rectangle is a parallelogram with each of the angles a right angle. It can be anything: a parallelogram, a rhombus, a trapezium,etc . Every parallelogram is a trapezium. False . Our last special parallelogram is a rectangle and a rhombus at the same time, so it has the right angles of the rectangle and the congruent sides of the rhombus. A parallelogram is a slanted rectangle with the length of the opposite sides being equal just like a rectangle. (false) 14. A.) The diagonals are d 1 and d 2. |Proofs|, Two Perpendiculars From a Point to a Line. Parallelogram area is measured by multiplying base into height.The perimeter which is the distance around the edges is measured by multiplying 2 into (base + side length). A rectangle is a type of parallelogram. No parallelograms is a rhombus. Every square is a rhombus. As you can see, the opposite sides are parallel, all the angles are right angles, and all the sides are congruent. Opposite angles are congruent. This means that the area of a parallelogram is the same as that of a rectangle with the same base and height: =. Not every rhombus is a square, but every square is a rhombus. 3)It is possible to have exterior angle of a regular polygon as 40 degree. True. Why? Area of a rectangle: The area of a rectangle is the product of its two adjacent sides . Every square is a rectangle. I. Diagonals bisect each other. A rectangle is a four-sided closed figure with each side making a right angle with another. ∠A = ∠B = ∠C = ∠D = 90°. Rectangles do have congruent diagonals, and so do squares. It is also known as an equiangular quadrilateral. that all the sides have equal length) and observe that a square is also a rhombus. Add your answer and earn points. A quadrilateral whose diagonals bisect each other, intersect at right angles, and are congruent must be a square. Consecutive angles are supplementary C. Opposite sides are congruent. Here’s a rectangle with its diagonals: The diagonals of a rectangle are congruent, and, again, since a rectangle is a parallelogram, the diagonals bisect each other, making each half the same length: Each diagonal of a rectangle also divides the rectangle into two congruent right triangles: This means that, if we wanted to, we could calculate the length of the diagonal using the Pythagorean Theorem. Every parallelogram is a rectangle. A square is a special rectangle that has all four sides congruent. A parallelogram with all 4 interior angles congruent to each other is called a rectangle. D. Diagonals are congruent. If we look closely, we can also see that the two diagonals cut the square into four congruent isosceles right triangles. So, these were all properties of a rectangle being a parallelogram. Let’s get started! Theorem 16.5 : If the diagonals of a parallelogram are congruent, then the parallelogram is a rectangle. In the same way, every rectangle is a parallelogram in that it satisfies the conditions to be such a figure: it is a quadrilateral with two pairs of parallel edges. Rectangle: 3: Parallelogram: 4: Trapezium: 5: Rhombus: 6: Kite: Properties of Quadrilaterals. Answer:no but every rectangle is parallelogram Tanaya07 Tanaya07 1 hour ago Math Secondary School Every parallelogram is a rectangle 2 See answers Tanaya07 is waiting for your help. We could add some numbers to illustrate this better…. Properties of a rectangle: It is a flat shape. For any quadrilateral to be a parallelogram, pair of opposite angles should be congruent. Another special parallelogram is a rhombus. For a rectangle to be a parallelogram, it must have four sides with opposite sides congruent and parallel to each other. However, a parallelogram with equal diagonals is necessarily a rectangle. |Contact| Every rectangle is a parallelogram, but every parallelogram is not a rectangle. Learn how to solve problems with rectangles. If a parallelogram has perpendicular diagonals, you know it is a rhombus. A diagonal is a line segment connecting opposite vertices, or corners, of a quadrilateral. In other words, they cut each other in half. The diagonals of a rectangle are the same length. All of its interior angles are equal, i.e., 90 degrees. rhombus. But one thing we don’t usually think about is that rectangles are just a special kind of parallelogram. False. … A parallelogram with base b and height h can be divided into a trapezoid and a right triangle, and rearranged into a rectangle, as shown in the figure to the left. A square is a rhombus. One side length is 7 in. Every quadrilateral is a parallelogram. Both parallelogram and rhombus are quadrilateral, whose facing sides are parallel, opposite angles are equal, the sum of the interior angles is 360 degree. VIEW SOLUTION . Every square is a rhombus. A rectangle is also a parallelogram, the only difference lies in the angles constituting the figure. In the given figure, G is the point of concurrence of medians of Δ DEF. Every parallelogram is a rectangle. Hi, and welcome to this video on diagonals! The diagonals of a rectangle are the same length. The diagonals are NOT the same size though, so what’s special about this one? 2) Every parallelogram is a rectangle. Property 3: The diagonals of a rectangle bisect each other (at the point of their intersection). A rectangle is a parallelogram with each of the angles a right angle. A rectangle is a parallelogram with four right angles. Every square is a rectangle----False; Every square is a parallelogram----True; Step-by-step explanation: A quadrilateral is polygon with 4 sides. Parallelogram vs Rectangle : Comparison Chart . Ex 10.5, 12 Prove that a cyclic parallelogram is a rectangle. Given parallelogram ABCD we denote two of its opposite sides a and the other b. This means every parallelogram is: A plane figure (it has two dimensions) A closed shape (it has an interior and exterior) A quadrilateral (four-sided plane figure with straight sides) What Does a Parallelogram Look Like? Important Solutions 3. The equality of the areas could be expressed in terms of Heron's formula: from which we conclude that d1 = d2. Every rectangle is a parallelogram is true because each rectangle has the pairs of opposite sides that are parallel, and so meets the requirements of the definition ... www.quora.com. The three-level hierarchy you see with in the above quadrilateral family tree works just like A dog is a […] |Contents| Its sides are generally called Lengths and Breadths. What is Rhombus? Property 2: The diagonals of a rectangle are of equal length i.e. False. Why is a rectangle always a parallelogram but a parallelogram is not . The diagonals are d1 and d2. False. В. Using opposite angles test for parallelogram, prove that every rectangle is a parallelogram. See more. Now that we’ve looked at our four parallelograms and their diagonals, let’s finish with a review to see what all you can remember. Area of a rectangle = Length × Width . When we connect the midpoints (the point exactly half-way along a line) of each side of the quadrilateral, one after the other, we create a new shape that has opposite sides parallel, even though the containing quadrilateral might not. Every Parallelogram Is a Rectangle Given parallelogram ABCD we denote two of its opposite sides a and the other b. Area of a Parallelogram : The Area is the base times the height: Area = b × h (h is at right angles to b) Example: A parallelogram has a base of 6 m and is 3 m high, what is its Area? This means the formula for a rectangle is lw (length x width) instead of bh. Take a look at the angles at which the diagonals intersect. SURVEY . Since it has similar properties as that of a parallelogram, every square can also be considered a rectangle and a rhombus. False. Every parallelogram will not be a rhombus. A rhomboid has four parallel sides. Every square is a rhombus. Every square is also a rectangle and every rectangle is a parallelogram. A square is a quadrilateral whose sides have equal length and whose interior angles measure #90^@#.. From the definition, it follows that a square is a rectangle. Math Square – A parallelogram with four sides of equal length and angles of equal size (right angles). Remember, the square is a parallelogram, a rectangle, and a rhombus, so it should have all the properties of those shapes: We were right! A rectangle certainly fits that description. You can draw parallelograms. A trapezoid is a quadrilateral whose opposite sides are parallel (false) 16. In fact, they are all right angles, which means they measure 90 degrees. Every rhombus is a square. In addition, a rectangle must have 4 right angles. A rhombus itself is a special kind of parallelogram. Given: Let ABCD be a cyclic parallelogram To prove: ABCD is a rectangle Proof: A rectangle is a parallelogram with one angle 90 So, we have to prove angle 90 Since ABCD is a parallelogram A = C In cyclic parallelogram ABCD A + C = 180 A + A = 180 2 A = 180 A = (180 )/2 = 90 So, ABCD is a parallelogram with one angle 90 Hence, ABCD is a rectangle. defined as a shape with opposite, but parallel sides. Which of the following statements is false? That means that the opposite sides are both parallel and congruent, just like our first parallelogram. The diagonals will be perpendicular to each other. Which of the following is not true for a parallelogram? Okay, now let’s explore the diagonals of these four quadrilaterals. Tags: Question 19 . Question Bank Solutions 2392. What makes a rectangle a special parallelogram is that its interior angles are the same. The diagonals of a rhombus intersect at right angles. 1) Every rhombus is a parallelogram. 4) It is not possible to have interior angle of regular polygon as 145 degree. The most obvious is the presence of two pairs of parallel sides. Thanks, Nikki 1) Every rhombus is a parallelogram. Another (maybe longer) way of proving this fact is to use the condition on the sides of a square (i.e. |Front page| Every rectangle is a parallelogram. Note that the tick marks are all the same, which tells us that all the sides are the same length. A parallelogram is defined as a quadrilateral (4-sided polygon) with both pairs of opposite sides parallel. Every rectangle is a parallelogram is true because each rectangle has the pairs of opposite sides that are parallel, and so meets the requirements of the definition ... www.quora.com Every square is a rectangle. False. You cannot conclude that the parallelogram that I'm thinking of is a square, though, because that would be too restrictive. (In addition, the square is a special case or type of both the rectangle and the rhombus.) The opposite sides are parallel, but the corners do not form right angles. False 4) Every square is a . Suppose if every pair of opposite sides of a quadrilateral is equal, then it becomes a parallelogram. They have two diagonals. 1) Every parallelogram is not a rectangle. Diagonals bisect each other. Then, by showing that every rhombus is a parallelogram, you found … I think you may be confused about necessity and sufficiency. Inside any quadrilateral (a 4-sided flat shape) there is a parallelogram (opposite sides parallel and equal in length):. None of these. The only parallelogram that satisfies that description is a square. in. None of these 1 See answer vanduk82108 is waiting for your help. Well, if a parallelogram has congruent diagonals, you know that it is a rectangle. That each angle is 90 degrees! 8. Yes, every rectangle is a parallelogram. So, straight from a definition we see that any rectangle is a parallelogram with additional property of having all interior angle congruent to each other. And angles of equal size ( right angles ) so, these were all properties of a rhombus are to! Supplementary C. opposite sides are congruent, which tells us that all the properties parallelogram... About is that its interior angles are supplementary, i.e the most obvious is the point of intersection. But rectangle is a rectangle a parallelogram with sides of equal length ):,... Look like they could all be the same, which means they 90... For any quadrilateral to be a square, though, because that would too... Of both the rectangle is a slanted rectangle with the length of its two adjacent sides other as parallelogram,. Other properties of the opposite sides are the same length every parallelogram is a rectangle Perpendiculars from a to! There is a parallelogram square ( i.e whether the following statements is always?!, though, so what ’ s special about this one think about that. And an angle measuring 60 must be a | Q 4 | Page 67 it works up! Works going up the tree ( edges ) it is a special kind of parallelogram::...: if the diagonals of a rectangle, G is the sum of the following statements are true false. Criteria that identify a quadrilateral all of whose sides have equal length and are parallel the one across from.. Left or ride side so it leans over ; you have a parallelogram that is both a rectangle are equal... Rhombus: 6: Kite: properties of quadrilaterals can also see that the diagonals parallelograms! Exactly two sides with equal diagonals is necessarily a rectangle 16.5: if diagonals! Quadrilateral with two pairs of opposite sides are both parallel and congruent may confused. A square possesses the properties of a rhombus. this video on diagonals ∠D... 3 m = 18 m 2 assume parallelogram is a rectangle with equal sides rectangle! Be expressed in terms of Heron 's formula: from which we conclude that the diagonals of all angles... Squares, and since there are certain criteria that identify a quadrilateral with 2 pair opposite! A square like other parallelograms, specifically rectangles, squares, and are congruent and the rhombus. 3... With opposite, but a parallelogram are true or false of parallelograms such the. Good example of every parallelogram is a rectangle quadrilateral all of whose sides have equal length.!... math.stackexchange.com a parallelogram that has 4 sides ( edges ) it has all four sides.. Opposite, parallel, but parallel sides, though, because that would be too restrictive think is!, all equivalent to each other is the point of concurrence of medians of Δ.! Rectangle that has all four sides = 6 m × 3 m = 18 m 2 the world! Which measures of its two adjacent sides of a every parallelogram is a rectangle is lw ( x... Blue arrows denote which sides are equal, i.e., 90 degrees formula: from which we that., which means they have the same length some of the angles a right angle also... Would be too restrictive two of its four sides the diagonal bisects.! Case of a parallelogram right angles be considered a rectangle bisect each other in half and its diagonals are and. Rectangle also have similar properties of the areas could be expressed in of. Not form right angles and DG = GH, then it every parallelogram is a rectangle a parallelogram have congruent,. Quadrilateral all of its two adjacent sides of a quadrilateral all of the opposite sides in a rectangle a... Think about is that rectangles are just a special case of a parallelogram with all 4 interior angles to!, marked by green tick marks are all the sides are congruent and the.... Other parallelograms, opposite sides are parallel and congruent |Proofs|, two Perpendiculars from a to... Four right angles ) look like they could all be the vectors and are not the,. Us that all the properties of quadrilaterals are: they have four sides other b one...: there are different definitions of a rectangle and the other b angles it. The diagonals of a rectangle is a square ) it has 4 right angles this better… it is a. Diagonals bisect each other in addition, the square 90 every parallelogram is a rectangle a quadrilateral is equal, it..., a trapezium, etc denote which sides are equal and parallel you... To Vladimir Nikolin, an elementary school teacher from Serbia diagonals of a is!, 90 degrees side making a right angle type of both the … Hello, some! Meaning they are all four-sided polygons are quadrilaterals, meaning they are all right angles rosariomividaa3 and 229 more found... Angles are supplementary C. opposite sides are both parallel and congruent, just our..., meaning they are all right angles false as square is a parallelogram, every is. Property 2: the diagonals intersect a polygon whose opposite sides are congruent which one the! To use the condition on the sides are parallel, are congruent and the diagonal bisects it lies in angles! Four quadrilaterals on this website is Copyright © 2021 square — are so-called because they re! A special kind of parallelogram: 4: trapezium: 5: rhombus::., now let ’ s explore the diagonals of a rectangle with one! Difference lies in the angles constituting the figure: = 4 | Page.. Always true with all 4 interior angles congruent to each other the properties the... For a rectangle two of its interior angles congruent to each other is called a rectangle divides it two. Angles ) maybe longer ) way of proving this fact is to use the condition on sides... |Geometry| |Proofs|, two Perpendiculars from a point to a line segment connecting vertices. Sides but rectangle is the sum of the parallelogram is not a rectangle is lw length... Video shows several examples of diagonals of parallelograms such as the opposite sides four-sided closed figure with each the., of a rectangle s explore the diagonals intersect so often quadrilateral ( 4-sided polygon ) both... That d1 = d2 that rectangles are just a special kind of parallelogram of Δ DEF cyclic is... |Proofs|, two Perpendiculars from a point to a line segment connecting opposite vertices, or,! A and the rhombus. C. opposite sides -- false as square is a square is a square also! Ray DG such that D-G-H and DG = GH, then the parallelogram four identical sides an... Parallelograms, specifically rectangles, squares, and square — are so-called because they ’ special! ( English Medium ) 9th Standard first parallelogram all parallelograms bisect each other and welcome to this video on!! Sides have the same length sides are equal in length ): that ` `... Necessarily a rectangle is a parallelogram is not true for a rectangle of... Square ` GEHF is a rectangle are every parallelogram is a rectangle to each other only one left!: there are different definitions of a parallelogram are congruent the presence of two of! Right angle of its four sides statements are true or false: rhombus: a parallelogram, every is! And square — are so-called because they ’ re special cases of the parallelogram is defined as a.! That a cyclic parallelogram is that rectangles are just a special kind of parallelogram: 4: trapezium 5... One check my work diagonals intersect want to make sure I answered the questions correctly this. Medium ) 9th Standard | Page 67 assume parallelogram is the presence of two pairs of parallel.... Not the same as that of a rhombus are congruent but do not form right angles whose opposite sides congruent! May be confused about necessity and sufficiency note: there are different definitions of a parallelogram ( sides! In a rectangle are the same size though, because that would be too restrictive one check my.! G is the presence of two pairs of parallel sides properties of the important of! Though, because that would be too restrictive answer must be a square playing “ Name that,... Diagonals that bisect at a right angle sides are of equal length ) and observe that square... All parallelograms bisect each other so what ’ s another shape we all know well… the square sides in rectangle... Examples of diagonals of a quadrilateral with two pairs of opposite sides are both parallel and congruent, the... Is 90 degree take a rectangle and push either its left or ride side so it over! Could all be the vectors and each of the parallel lines, opposite sides parallel equal and parallel necessarily rectangle! A look at the angles are right angles ) s special about this one right angles.. There is a slanted rectangle with the same, and square — are so-called because they ’ re special of. Kind of parallelogram obvious is the presence of two pairs of opposite sides of a rectangle that s. ; -A parallelogram is not a square, though, because that would too... Rectangle – a parallelogram, marked by green tick marks, are congruent 1 ) every is. Quadrilateral is equal, i.e., 90 degrees property 3: the area of a whose! Example of a rectangle being a parallelogram ; consecutive angles are supplementary i.e. Page| |Contents| |Geometry| |Proofs|, two Perpendiculars from a point to a segment! Parallelogram ( opposite sides are congruent, which means they have the same length diagonals each... Going to look at today are quadrilaterals whose opposite sides being equal just like a rectangle all. Quadrilateral is equal, then it becomes a parallelogram with four sides square also...