WAEC 2023 · Paper 1 · Q27

The length of the diagonal of a square is $12\text{ cm}$ . Calculate the area of the square.

Worked solution (try it first)

The diagonal is the hypotenuse of a right-angled triangle whose legs are two sides $s$ : $s^2 + s^2 = 12^2$ .
So $2s^2 = 144$ , and the area is $s^2 = 72\text{ cm}^2$ , option C.