Jules needs to purchase a ladder that just reaches the top of a 16-foot building. If the bottom of the ladder will be placed 12 feet from the base of the building, how long should Jule's ladder be?

This is a simple direct application of the Pythagorean Theorem; a2 + b2 = c2 where a and b are the legs of a right triangle, and c is the hypotenuse:

A = 16
b = 12
Thus: 16 x 16 = 256
          12 x 12 = 144
          144 + 256 = 400
          √400 = 20

Thus, the ladder would need to be 20ft long to just reach the top of a 16ft tall building if the base is set 12ft from the face of the building.

Hope that helps, and you have a great day!