Converse blanks: the sum of the legs squared is equal to the square of the hypotenuse; right.
a = 27, b = 36 (a and b can be switched), c = 45 --> the hypotenuse is always the longest side.
a² + b² = c²
Substitute: 27² + 36² = 45²
Simplify: 729 + 1296 = 2025
Simplify: 2025 = 2025
This is a right triangle because the sum of the lengths of the legs squared is equal to the length of the hypotenuse squared.
(also good note, the sides have a ratio of 3 : 4 : 5, which will always make a right triangle)