use the cos and sin rules.. so if x is adjacent to 30 degrees then cos(30)= x/10 therefore x= 10cos(30). The opposite side which would be y which will be sin(30)=y/10 therefore y=10sin(30)
to cheak it u can put in (10sin(30))^2+(10cos(30))^2 which would = to 10^2 therefore the hypotenuse would be 10 ^_____^ tada!~