Question

A vertical stick of length 6 m casts a shadow 400 cm long on the ground and at the same time a tower casts a shadow 28 m long. Using similarity, find the height of the tower

Answer 1

In ∆ABC and ∆PQR,

∠ABC = ∠PQR = 90° ...(Vertical Stick)

∠ACB = ∠PRQ  ...(Same time casts shadow)

∆BCA ~ ∆QRP


`"AB"/"PQ" = "NC"/"QR"`

`6/x = 4/28`

4x = 6 × 28

⇒ x = `(6 xx 28)/4` = 42

Length of the lamp post = 42 m