Are the diagonals of a rectangle always, sometimes or never congruent?

1 Answer
Nov 18, 2015

Diagonals of a rectangle are always congruent.

Explanation:

Proof

In a rectangle ABCDABCD sides ABAB and CDCD are congruent and parallel, sides ADAD and BCBC are congruent and parallel, all internal angles are 90^o90o.

Therefore, triangles Delta ABC and Delta ABD are congruent as right triangles with one cathetus AB shared among them and another pare of catheti, BC and AD, being congruent.

Hence, their hypotenuses AC and BD are congruent.