The Pythagorean Theorem would be useful here. If you have a triangle with side lengths a, b and c, and c is the longest side, then the triangle is a right triangle only if a^2 + b^2 = c^2.
Look at side lengths 14, 24 and 26. Does 14^2 + 24^2 = 26^2?
Does 196 + 576 = 676? NO.
In this particular case we do NOT have
a right triangle.