Prove that the diagonals of a rectangle are equal. [3 MARKS]
Concept : 1 Mark
Proof : 2 Marks
Consider a rectange ABCD
AD=BC and AB=CD [ Opposite sides of a rectange]
∠A=∠B=∠C=∠D=90∘
⇒BD2 = AD2+ AB2 --------(i)
and AC2 = AB2 + BC2
⇒AC2 =AB2+ AD2 --------(ii) [ since BC=AD ]
From (i) and (ii) AC2 = BD2
⇒AC=BD
Hence, the diagonals of a rectangle are equal.