For incidence from dielectric medium (∈1) into dielectric

For incidence from dielectric medium (∈₁) into dielectric medium 2 (∈₂), the Brewster angle θ_p and the corresponding angle of transmission θ_t for ∈₂/ ∈₁ = 3 will be respecitively—

Brewster angle
tanθ₁ = √∈₂/∈₁
= √3
Therefore, θ₁ = 60º
and sin θ₁ = √∈₂
sin θ₂ = ε₁

sin 60°	= √3
sin θ₂

solving, we getθ₂ = 30º