Answer: No, it is not a right triangle
Step-by-step explanation
We have a triangle with the side lengths of: a = 8, b = 9, c = 12
Plug those values into the pythagorean theorem. If we get the same thing on both sides, then we have a right triangle.
a^2 + b^2 = c^2
8^2 + 9^2 = 12^2
64 + 81 = 144
145 = 144
The two sides are very close to the same value, but aren't the exact same number. Since we get a false equation at the end, it means a^2 + b^2 = c^2 is false when (a,b,c) = (8,9,12)
Therefore, we do NOT have a right triangle with side lengths 8 cm, 9 cm, 12 cm.