Question

Prove that diagonals of a rectangle are equal in length.

Answer 1

Consider a rectangle $ABCD$ in which let $AC$ and $BD$ be the diagonals.

Then, there are two triangles obtained and they are $\Delta ABC$ and $\Delta BCD$

The angle that is common between the two triangles is $\angle b$.

The common side is $BC$

Hence, $AB=CD$

Therefore, $\Delta ABC$$\cong$$\Delta BCD$

Also, $AC=BD$…………………(corresponding sides of congruent triangles)

Hence, it is proved that the diagonals of a rectangle are equal in length.