The base of a 12 foot ladder is 3 feet from the building.

Question

The base of a 12 foot ladder is 3 feet from a building. If the latter reaches the flat roof, how tall is the building?

Height ___

Height (approximately) ___ round to the nearest tenth.

Answer 1

b^2 = 12^2 - 3^2 = 144 - 9 = 135

b =sqr135 = about 11.62 feet tall building

draw a sketch, it helps. you know the building is a little less than 12 feet

or you can use trigonometry and a calculator with an inverse trig function

b = 3tanA where A is the angle between sides 12 and 3

A = the angle whose cosine = 3/12 = 1/4

A = about 75.52

tanA = about 3.873

b = 3x 3.873 = about 11.62 feet