Height of pole = 4 m
Length of shadow= 5.2 m
The tan of angle made at that time = height of pole / length of shadow
So tan a = 4/5.2
Similarly tan a = height of pole / 91 ( for the second pole)
On equating ,
4/5.2 = h/91
h=(91*4)/5.2 = 364/5.2
= 70
Like if satisfied