Please help me out with this physics problem!?

Question

The critical angle for total internal reflection at a diamond-air boundary is 24.4 degrees. What is the angle of refraction in the air if light enters boundary at an angle of 20.0 degrees?

Answer 1

sin(θ cri)=(n_r/n_i)

For air nr=1

sin(24.4)=(1/n_i)

ni=2.42

From the Snell's law

(n1/n2 )=(sinθ2/sinθ1)

1/2.42=sinθ2/sin20

sinθ2=0.1413

θ2=8.123

Angle of refraction is 8.123