Question 179646
Here is a simple example:
Say you have a ladder that is 52 feet tall. Assuming that the base of the ladder must be at least 20 feet from the building, how hight up can the ladder reach?

This is a right triangle, with base 20 feet and hypotenuse 52 feet:
20^2 + b^2 = 52^2

{{{b^2 = 52^2 - 20^2}}}

{{{b = sqrt(52^2 - 20^2)}}}

b = 48 feet

The ladder can reach 48 feet up the building.