A prism with an angle A=60° produces an angle of minimum deviation 30°.Then the refractive index of the material of prism

A convenient way to measure the refractive index of a prism is to direct a light ray through the prism so it produces the minimum deviation angle. This yields a simple formula:
n=sin(A+D)/2/sin(A/2)
where n is the refractive index at a wavelength λ, D is the angle of minimum deviation, and A is the internal angle of the prism
in question given that
A=60°. D=30°
n=sin45/sin30
=1/√2/1/2
=2/√2
n=√2