Which of the lengths could NOT be the sides of a right triangle?

Question

5 cm, 12 cm, 13 cm

5 cm, 6 cm, 8 cm

8 cm, 15 cm, 17 cm

3 cm, 4 cm, 5 cm

Answer 1

The one that could NOT be the sides of a right triangle is:

8 cm, 15 cm, 17 cm

Because when we apply the Pythagorean Theorem, we get:

a² + b² = c²

8² + 15² = 64 + 225 = 289

Taking the square root of both sides we get:

√289 = 17

This means that the three sides form a triangle, but it is not a right triangle because the longest side (17 cm) is not the hypotenuse. Therefore, the correct answer is 8 cm, 15 cm, 17 cm.