Question

The length of the diagonal of a square is $10\sqrt{2}$ cm. Its area is

(a) 200 $c{m}^2$ (b) 100 $c{m}^2$ (c) 150 $c{m}^2$ (d) $100\sqrt{2}c{m}^2$

Answer 1

Diagonal = $\sqrt{2}$ side of square
let side be = a
$10\sqrt{2}=\sqrt{2}a$
10 = a

Area = Side$\times$Side
= 10 $\times$ 10
= 100
= $100c{m}^2$