The concept to answer this question can be bought from physics.
The Snell's law of refraction says that, the ration of sine of angle of incidence to the the sine of angle of refraction is constant for a given media.
This means;
(sinθ1)/(sinθ2) = k
Where θ1 = angle of incidence and
θ2 = angle of refraction
k = constant
(sinθ1)/(sinθ2) = k
sinθ2 = k/sinθ1
= k/sin25
= k/0.422618261
= 2.366k
The angle of refraction, θ2 = anti-sin(2.366k)
