Question

Is the triangle formed by the sides of lengths 9 cm, 40 cm, and 41 cm a right-angled triangle?

Answer 1

For any lengths to be sides of a right angled triangle, the sum of the squares of the two of them should be equal to the square of the third.

Here,

$9^2+{40}^2=81+1600=1681={41}^2$

Since the squares of 9 and 40 add up to the square of 41, these form a Pythagorean triplet

Hence, they can be used to represent the three sides of a right-angled triangle.