Question

A boy is looking at the top of a building which is 10 m high.
From the figure, the distance between the boy and the building will be_______ .

• A. 5 m
• B. 10 m
• C. 15 m
• D. 20 m

Answer 1

The correct option is B 10 m


Here, XB and AC will be the horizontal.
From the above figure, we can write,
$\angle XBA=\angle BAC=45°$
$\text{[Alternate interior angles]}$

$\text{Therefore, in}△ACB,$
$tanA=\frac{BC}{AC}$
$\Rightarrow tan45°=\frac{10}{AC}$
We know that, $tan{45}^o=1$.
$\Rightarrow 1=\frac{10}{AC}$
$\Rightarrow AC=10m$

Hence, the distance between the boy and the building will be 10 m.