hey! so this is actually a really simple question if you memorized the 30 60 90 special triangle (search it up online, it'll help SO MUCH)
in general, using a as a variable, the hypotenuse is 2a, the shortest length (the length opposite the 30 degree angle) is a, and the other side (x, in this diagram) is a√3
therefore, for this diagram:
y=10
x=5√3
hope this helps!