Question:
What is the angle of elevation of the Sun when the length of the shadow of a vetical pole is equal to its height?
Solution:
Let
be the angle of elevation of sun is
.

Given that: Height of pole is
meters and length of shadow is
meters. Because length of shadow is equal to the height of pole.
Here we have to find angle of elevation of sun.
So we use trigonometric ratios.
In a triangle
,
$\Rightarrow \tan \theta=\frac{A B}{B C}$
$\Rightarrow \tan \theta=\frac{h}{h} \quad\left[\because \tan 45^{\circ}=1\right]$
$\Rightarrow \tan \theta=1$
$\Rightarrow \theta=45^{\circ}$
Hence the angle of elevation of sun is $45^{\circ}$.