first of all, you're combining your equations. the area of a triangle in this case is not .5 base xheightsin(ang), it's .5 (side a) (side b) sin (ang). to find the side, just plug your values in and you should have only 1 unknown.

I got 10.0087

Work:

area=.5(sidea)(sideb)sin(angle)

sin(73) * 0.5 * 7 * b= 33.5

33.5/sin(73) * 0.5 * 7 =b

b= 10.0087

I think i'm right, check me and let me know if my math is wrong.