a^2 + b^2 = c^2
C should equal to the longer side, which would be 19.
Plug in other two numbers for A and B.
12^2 + 14^2 = 19^2
Now see if it's correct. If it is, then it's a right triangle, if it's not then it isn't a right triangle.
144 + 196 = 361
340 = 361
It's not a right triangle.
