This is a problem for which you will have to use the Pythagorean theorem.
The Pythagorean theorem states that:
x^2 + y^2 = h^2
where x and y are the legs, and h is the hypotenuse.
Let h = 20 ft, and x = 16
16^2 + y^2 = 20^2
Now, solve for y.
256 + y^2 = 400.
256 - 256 + y^2 = 400 - 256
y^2 = 144
y = 12
The length of the other leg is 12 feet.
