Question

The area of a square is 200 cm square . What is the length of its diagonal?

Answer 1

$a {}^{2} = 200 \\ a = 10 \sqrt{2} \\ to \: find \: diagonal \: multiply \: length \: of \: one \: side \: with \sqrt{2} \\ (i.e) \: d = 10 \sqrt{2} \times \sqrt{2} \\ = 10 \times 2 \\ = 20 \: cm$