By Pythagora's, adjacent = Sqrt(3^2 - 1^2) = 2sqrt(2)

tan theta = opp/adj = 1/2sqrt(2) = sqrt(2) / 4

you do the inverse of sin.

sin^-1(1/3) = (type into calculator)

tan(answer from sin inverse) = final answer

sorry, don't have a calculator on me.