Question

Determine whether the triangle whose lengths of sides are 3 cm, 4 cm, 5 cm is a right-angled triangle.

Answer 1

3² = 3 × 3 = 9;
4² = 4 × 4 = 16;
5² = 5 × 5 = 25

We find 3² + 4² = 5².
Therefore, the triangle is right-angled.