Definition: A rectangle is quadrilateral with 4 right angles (90°).
Rule: Opposite sides of a rectangle are congruent (of equal length).
Proof: By the definition of a rectangle, it follows that every rectangle is a parallelogram. We showed that opposite sides of a parallelogram are congruent. It follows that opposite sides of a rectangle are congruent.
Interactivity 1: Rectangles Directions for interactivity
Click and drag the slider buttons to change the size. Click and drag point B to move and point А to rotate.
|Basic formulas for rectangles with sides a and b: the perimeter is: L=2(a+b) , and the area is: A=ab .
Examples for perimeter and area of rectangles
Check the following examples using the above interactivity.
Interactivity 2: Construct a rectangle
The diagonals of a rectangle are congruent (the same length) Interactivity
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