Answer:
C. 5/3 (5 sqrt 3) (8.66...)
Step-by-step explanation:
You would use the SohCahToa to find out side x.
First, label your sides (10 is hypotenuse, x is the opposite, and blank side is the adjacent).
Second, figure out which part you have to use (Sin, Cosine, or Tangent). A good way to tell is of you have the missing side on top of the fraction, makes things easier.
Third, once you figure that out then plug stuff in...
Sin(theta) = O/H
Sin(60) = X/10
10sin(60) = X
8.66... = X