Which triangle with side lengths given below is a right triangle? Select Yes or No. A. 10, 15, 20
B. 10, 24, 25
C. 9, 40, 41
D. 11, 60, 61

In order to be a right triangle, by the Pythagorean theorem, the length of the longest side c must be equal to the square root of the sum of the squares of the other sides a and b. By this I mean c=sqrt(a^2 + b^2).

The only option that satisfies this condition is C, because 41=sqrt(81+1600).