If you're just solving for x and y, you can use one of the special right triangles: 30, 60, 90. The side opposite to 30 degrees will be variable 'a'. The side opposite of 60 degrees is equal to 'a' sqrt(2). And the hypotenuse is always 2 'a'.
Given that 'a' is 5:
x is about 7.071
y is 10.
I forgot the theorem so I can't help there.
