Question

two mirrors are placed at an angle of 72^o how many images are formed?

Answer 1

The total no. of images (n) formed in this case is given by :-
n = $\frac{{360}^0}{\theta }-1$ , if $\frac{360}{\theta }$ is even integer.
Calculating, we get :- n= $\frac{360}{72}$-1 = 4