Answer: No
Step-by-step explanation:
Pythagorean Theorem goes with a right triangle, the formula is a^2+b^2=c^2.
Let's try this out with your values.
(18*18)+(12*12) = 468
If this is true than c^2 is 468
c^2 or (22*22) is 484 is this is not a right triangle.
