A 25-foot ladder rests against a building. The base of the ladder is 15 feet away from the base

of the building. At what height does the ladder rest on the building?

Answer: the top of the ladder is 20ft below the ground.

Step-by-step explanation:

The ladder makes an angle, θ with the ground thus forming a right angle triangle with the wall of the house.

The length of the ladder represents the hypotenuse of the right angle triangle.

The ground distance between the base of the house and the base of the ladder represents the adjacent side of the right angle triangle.

Therefore, to determine the height at which the ladder rest on the building, x, we would apply Pythagoras theorem which is expressed as

Hypotenuse² = opposite side² + adjacent side²

25² = x² + 15²

625 = x² + 225

x² = 625 - 225 = 400

x = √400 = 20 ft