Question

Julia is standing 2 feet away from a lamppost. If she casts a shadow of 5 feet and the light makes a 20° angle relative to the ground from the top of her shadow, how tall is the lamppost?

Answer 1

2.5477 feet

Explanation:

Refer the image attached to understand my solution.

BC = height of lamppost.

DE = Julia

AD = shadow of Julia

BD = 2 feet. AD = 5 feet

BA = BD + AD

= 2 + 5 = 7 feet

In ΔABC

tan 20° =
`(BC)/(BA) = (BC)/(7)`

BC = 7 * tan 20°

BC = 2.5477 feet

SO the height of lamppost = 2.5477 feet