Quadratic equations

Question

The bottom of a ladder must be placed 18 feet from a wall. The ladder is 24 feet long. How far above the ground does the ladder touch the wall?

Answer 1

Ladder and wall form a right triangle, with 24 feet length the hypotenuse and bottom of ladder distance from wall forming a leg. Height of ladder is other leg. Can use Pythagorean Theorem to find the height:

24^2 = 18^2 + height^2