Question

How do you use the Pythagorean Theorem to determine if the three sides are a right triangle: 15 m, 12 m, 9m?

Answer 1

We need to check that the sum of the squares of the lengths of the two shorter sides is equal to the square of the length of the longest side.

`9^2+12^2 = 81+144 = 225 = 15^2`

Actually, we could have noticed that all the sides are a multiple of 3m, namely `5xx3`m, `4xx3`m and `3xx3`m, so we have a 3,4,5 triangle - just 3 times larger.

`3^2 + 4^2 = 9+16 = 25 = 5^2`