Question

Find the length of the diagonal of a square whose side is 'a' units.

Answer 1

Using Pythagoras theorem for the right angle triangle formed by the two sides and the digonal of the square, we get
$a^2+a^2=d^2$ where d is the diagoanl of the square, say.
Thus, d = $\sqrt{2a^2}$ = $\sqrt{2}a$