Answer:
The answer to your question is:
a) 8.2 mi
b) 4.1 mi
c) 4.7 mi
Explanation:
For 30°
sin Ф = opposite leg / hypotenuse
hypotenuse = opposite leg / sin 30
hypotenuse = 4.1 / sin 30 = 4.1 / 0.5
hypotenuse = 8.2 mi
For 90°
d must be 4.1 mi because is over the observer at this angle
For 120°
distance = opposite leg / sin 60
distance = 4.1 / √3/2
= 4.71 mi
I hope it helps you!