Question

A 16 foot ladder rests against the side of a house and the base of the ladder is 4 feet away. How high above the ground is the top of the ladder?

Answer 1

C squared - a squared = b squared. 16 squared - 4 squared =240. Square root of 240 = 15.49. It is 15.49 feet.

Answer 2

Use the Pythagorean theorem. 

a^2 + 4^2 = 16^2

a^2 + 16 = 256 

a^2 = 240

a = √240 = 15.4919. . .