Which set of three numbers could represent the lengths of the sides of a right triangle?

A.

7, 24, 25

B.

8, 9, 10

C.

9, 11, 14

D.

15, 18, 21

All you have to do is use the Pythagorean theorem (a² + b² = c²) on all of them. Since, the hypotenuse is always the longest side, use the biggest number for c.

A: 7² + 24² = 25²

49 + 576 = 625

625 = 625

Luckily, the answer is A.