math
posted by evelyn .
A 13 foot ladder is leaning against a building.The bottom of the ladder is 5 feet from the building.How high up does the ladder meet the wall?

Use the Pythagorean Theorem.
a^2 + b^2 = c^2
a^2 + 5^2 = 13^2
a^2 + 25 = 169
a^2 = 169  25
a^2 = 144
a = 12