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

The ratio of shadow to the height would remain the same

When height is 3 m the shadow is 4 m

⇒ ratio = = …(i)

When shadow is 24 m let the height be ‘a’ m

⇒ ratio = =

Using (i)

⇒ =

Cross multiplying

⇒ 24 × 3 = 4 × a

⇒ a = = 6 × 3

⇒ a = 18

Height of the flagstaff is 18 m