Question

The shadow of a 3 m long stick is 4 m long. At the same time of the day, if the shadow of a flagstaff is 24 m long, how tall is the flagstaff?

Answer 1

Let the length of flagstaff is x.

Shadow: Length :: Shadow : Length

4 m : 3 m :: 24 m : x

`4/3 = 24/x`   ...`["If a, b, c and d are in proportion" a/b = c/d]`

4 × x = 3 × 24  ...[By cross-multiplication]

`x = (3 xx 24)/4`

x = 18

Hence, the flagstaff is 18 m tall.