Answer:
To determine the value of X, what you would need to do is to use a trigonometric ratio, that would make use of the value of x and the side length of 12. This can either be, sin 30 or cos 60. Both of them will enable you to solve for x.
The final value for x would be either
X = 12/Sin 30
X = 12/Cos 60
Compute these in your calculator and you will find the final value in these cases.
