Question

A pole 24 feet high has a shadow eight feet long. A nearby pole is 72 feet tall. How long is it's shadow?

Answer 1

length of shadow of pole will be `24\ \text{feet`

Explanation:

The light rays coming from the sun are almost parallel.

Thus, we get two similar right triangles formed by the heights of poles `h_1=24\ \text{feet` & `h_2=72\ \text{feet` & respective lengths of shadows `d_1=8 \text{feet` & `d_2 \text{feet`

Ratio of corresponding sides of two similar triangles is same

`d_2/d_1=h_2/h_1`

`d_2/8=72/24`

`d_2={72\cdot 8}/{24}`

`=24`

hence the length of shadow of pole of height `72\ feet` will be `24\ \text{feet`