prove that a rectangle is a parallelogram.

Asked by  | 2nd Jul, 2009, 10:52: PM

Expert Answer:

let ABCD be a rectangle

to prove that it's a parallelogram, we must show that either one pair of opp sides is parallel and equal


 both pairs of opp sides are parallel.

angle A=90 degrees

angleD=90 degrees


AB and CD are parallel(int angles on the same side of the transversal are supplementary)


AC and BD  can be shown parallel.

So ABCD is a parallelogram.

As such,

 the definition of a rectangle is that it's a parallelogram with one angle as  a right angle.

Answered by  | 2nd Jul, 2009, 11:13: PM

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