Question

When a small plane mirror is placed horizontally on level ground at a distance of $60m$ from the foot of a tower, the top of the tower and its image in the mirror subtend an angle of $90^{\circ }$ at the eye, where eyes is placed at the mirror itself. Find the height (in meter) of the tower.

Answer 1

Answer: 60.00

$\angle A{M}_{1}E=90^{\circ }$
There fore $\angle A{M}_{1}B=90^{\circ }$
Hence $\angle A=\angle B=45^{\circ }$
and $\tan 45^{\circ }=\frac{O{M}_1}{OA}$
$\Rightarrow O{M}_1=OA=60m$