Question

Please help use the diagram of the right triangle above

Answer 1

For this case what you have to take into account is the following trigonometric relationship:
TanB = b / a
We clear the value of b:
b = a * TanB
Substituting the values we have:
b = 10 * Tan (60)
b = 17.32 m
Answer:
b = 17.32 m
option a.