How do you find the third side if a right triangle?

A^2 + b^2=c^2 so let's say you are solving for your hypotenuse which is the slanted non right angle side would be your c. if your dimensions of the right angle sides are 6 x8 your a would be 6 and your 8 would be b. your equation would look like 6^2 + 8^2 = c^2. 36+64 = 100 (your third side)

use the pythagorean theorem