Now substitute the values you know and the value you don’t know in the Pythagorean Theorem equation. We can use the variable a to represent the unknown side length. It has been labeled for you in the image. Use the variable a to represent the unknown length of the leg in the equation.

Width
? in
aLength
12 inCut
15 in
The Pythagorean Theorem says that if a, b, and c are the sides of a right triangle, where c is the hypotenuse, then:
a
2
+ b
2
= c
2
.