By using the Pythagorean theorem, we will see that side C measures 150ft.
How to get the length of side C?
We can see that side C is the hypotenuse of a right triangle. We know both catheti of said triangle, then we can use the Pythagorean theorem.
It says that the sum of the squares of the cathetus is equal to the square of the hypotenuse. Then we have:
A^2 + B^2 = C^2
We know that:
A = 90ft
B = 120ft
Replacing that we get:
√((90ft)^2 + (120ft)^2) = C = 150ft
Then we conclude that side C measures 150ft.
If you want to learn more about right triangles, you can read:
https://brainly.com/question/2217700