a 13 ft ladder is placed against a vertical wall of a building, with the bottom of the ladder stand on level ground 5ft from the base of the building. how high up the wall does the ladder reach.

Answer 1

The ladder is the hypotenuse of a right triangle.

a^2 + b^2 = c^2

5^2 + b^2 = 13^2

25 + b^2 = 169

b^2 = 144

b = 12