Answer:
a) the largest angle is 15.05°
b) index of refraction, h = 1.5112
Step-by-step explanation:
a)

90 - θ >

90 - θ >
= 74.95
90 - θ > 74.95
- θ > 74.95 - 90
θ > -74.95 + 90
θ > 15.05°
b)
90° -
>

90° - 5° >

85° >

h = 1.517 × Sin 85°
h = 1.517 × 0.9962
h = 1.5112