You can solve this problem by following the proccedure below:
1. You have:
Cos(α)=Adjacent/Hypotenuse
α=30°
Adjacent=7√3
Hypotenuse=w
2. When you substitute this values into Cos(α)=Adjacent/Hypotenuse, you obtain:
Cos(α)=Adjacent/Hypotenuse
Cos(30°)=(7√3)/w
3. When you clear "w", you obtain:
wCos(30°)=7√3
w=(7√3)/Cos(30°)
4. Then, the result is:
w=14
The answer is the last option: 14
