Question

A man of height $180$ cm is standing in front of a plane mirror. His eyes are at a height of $170$cm from the floor. Find the minimum height of the mirror?

Answer 1

HF = height of the man $=180cm$

E = Eye of human i.e. $HE=170cm$

Here it can easily be noticed that $AE=AH=POBE=OQ=BF$

Due to reflection, we need the mirror of the length $PQ$

Hence the height of the mirror = $\frac{HF}{2}=90cm$