Question 1153707
Very basic trigonometry, or use of special right triangles.  What help do you need?  You are asking for four different but related exercises.


#12:


You understand this is a special 30-60-90 Triangle?  It is HALF of an equilateral triangle?   {{{y=10/2=5}}}, and you should be able to figure what is x.
{{{x/10=sqrt(3)/2}}},...




#11:


This is a special 30-60-90 Triangle.  It is half of an equilateral triangle.  You KNOW that {{{2y=x}}}.   You could use Pythagorean Theorem to figure the values for x and y.  (Or, very simple trigonometry knowledge).


{{{y/(5sqrt(3))=cos(60)}}}
.
.