Student 1 and student 3 are equivalent
This might help it has tons of different problems for your subject.
https://www.wyzant.com/resources/lessons/math/algebra/calculators/proportion
You are given the opposite: 16 km
You need to find x (adjacent)
The angle measure: 28 degrees
With opposite and adjacent, use tangent
Tan(28) = 0.5317094317
Tan(28) = 16/x
x = 16/0.5317094317
x = 30.0916
Round to nearest tenth
Solution: x = 30.1 km
A would be the correct answer:)
Hope this helps!