Question

A plastic board that is 15 feet long is leaning against a wall

perpendicular to the ground. The point at which the wooden
board touches the wall is 12 feet above the ground. How far
away is the base of the board from the bottom of the wall?
feet

Answer 1

9 ft

Explanation:

a²+b²=c²

a²+12²=15²

a²+144=225

225-144=81

√81=9