Posted by anon on Wednesday, January 12, 2011 at 5:22pm.
sin A = 3/5 = a/c
if side a = 3 and side c = 5
you should recognize this as a
special rt triangle of 3-4-5
so b = 4
If not
a^2 + b^2 = c^2
3^2 + b^2 = 5^2
b^2 = 16
b = 4
so, a = 3, b = 4