Question

A 1.5m tall boy stands at a distance of 3m from a lamp post and casts a shadow of 4.5m on the ground.find the height of lamp post by trignometric ratios

Answer 1

....boy......................lamp post
............|........................|..(h) = ? 
.1,5m...|_________.|____________
............\...3m............./..\.......4,5m........./

directly proportional

Solution:

$\frac{1,5}{3} = \frac{h}{4,5}$

multiply cross and solving:

$3*h = 1,5*4,5$
$3h = 6,75$
$h = \frac{6,75}{3}$
$\boxed{\boxed{h = 2,25m}} \end{array}}\qquad\quad\checkmark$

Answer: the height of lamp post is 2,25 m