Show that diagonals of a Rectangle are equal.

A rectangle is a parallelogram with four right angles.

To show diagonals of a rectangle are equal.

Let ABCD be a rectangle with diagonals AC and BD.

Since in ABCD, ∠A=90⁰ and AD = BC

AD ∥ BC and AB is a transversal.

Hence, by SAS congruence of triangles, ΔABD ≅ ΔBAC

Therefore, by CPCT BD = AC.

Hence proved.