Question

a man of height 1.8m standing 5m awaya from lamp post, observe his shadow of length1.5m. find length of lamp post

Answer 1

Using similar triangle
So the ans is 7.8

Answer 2

$\huge\sf\green{Answer:-}$

• Let "H" be height.

• Height = 1.8 m.

• Let "x" be the distance between Man and Lamp post be = 3.6 m.

• ( y = 5.4 ) m is the distance of Shadow.

Hence :

$\sf = > Distance = (x+y). (Theta) \\ </p><p>\sf = > tan \: \: theta = \frac{h}{y} = \frac{1.8}{5.4} = \frac{1}{3} \: ->(Man) \\ \sf = > tan \: \: theta = \frac{h}{(x + y) } = \frac{h}{5.4 + 3.6} = \frac{h}{9} \: ->(lamp \: post)$

Calculation:

$\sf => \frac{h}{9} = \frac{1}{3} \\ </p><p>\sf => h = \frac{9}{3} = 3 m$

3 m = height of lamp post.