Question

Simon bought a new shop and wants to order a new sign for the roof of the building. From point P, he finds the angle of elevation of the roof, from ground level, to be 31º and the angle of elevation of the top of the sign to be 42º. If point P is 24 feet from the building, how tall is the sign to the nearest tenth of a foot?

Answer 1

Let y - x = height of sign

tan 31 = x/24

tan 31 • 24 = x

14.4206548567 = x

tan 42 = y/24

tan 42 • 24 = y

21.6096970631 = y

Now subtract x from y.

y - x = 21.6096970631 14.4206548567

y - x = 7.1890422064

Rounding off to the nearest tenth of a foot, we get 7.2 feet.

The sign for the roof is 7.2 feet.