prove that diagnals of a rectangle are of equal length
ABCD is a rectangle. AC and BD are the diagonals of rectangle.
In ΔABC and ΔBCD, we have
AB = CD (Opposite sides of rectangle are equal)
∠ABC = ∠BCD ( Each equal to 90°)
BC = BC (Common)
∴ ΔABC ΔBCD (SAS congruence criterion)
⇒ AC = BD [c.p.c.t]
Hence, the diagonals of a rectangle are equal.