11. A vertical stick long casts a shadow long. At the same time, a tower casts a shadow long. Determine the height of the tower.

Solution:

Given:

Length of stick =

Length of the stick’s shadow =

Length of the tower’s shadow = =

To find:

The height of the tower = PQ.

In ΔABC ∼ ΔPQR

∠ABC = ∠PQR = 90^o

∠ACB = ∠PRQ (Angular Elevation of Sun is same for a particular instant of time)

⇒ ΔABC ∼ ΔPQR    (By AA similarity)

AB/BC = PQ/QR (Corresponding sides are proportional)

Therefore,