For all of them just use the Pythagorean theorem which is a squared plus b squared equals c squared where c is the hypotenuse (length of the side opposite the right angle) and a and b are legs. Just plug it in and solve for the missing length. For example, 1 would be (12) squared plus (5) squared equals c squared
Simplify to get 144 plus 25=c squared
169 equals c squared
Find the square root of both sides
c=13
