What is the angle of incidence for an equilateral prism of refractive index 3 so that the ray is parallel to the base inside the prism?

3=sin⁡60∘+δm2sin⁡60∘232=sin⁡60∘+δm2sin⁡60∘=sin⁡60∘+δm2or 60∘+δm2=60∘or δm=60∘⇒i=A+δm2=60∘+60∘2=60∘μ=sin A+D2sinA2    IN minimum deviation position the light ray travels parallel to the base of the prism.μ=sin isin r