Answer :
[tex]From\ triangle\ with\ angles: 30^{\circ},60^{\circ},90^{\circ}\\\
|AB|=a\sqrt{3}\\
|AC|=a=9\\\\
|AB|=9\sqrt{3}\\\\
Length\ of\ |AB|\ is\ equal\ to\ 9\sqrt{3}.
[/tex]
Since you know angle B and length of ac, you can use the Sin ratio to determine the length of ab. Set up as Sin30 = 9/x. As sin= opp/hyp and x=unknown length.
Then cross multiply and divide. move x over to sin30, then move sin30 under 9.
So now you have x= 9/Sin30. enter in calculator, but make sure you are in degree mode!!!
Then cross multiply and divide. move x over to sin30, then move sin30 under 9.
So now you have x= 9/Sin30. enter in calculator, but make sure you are in degree mode!!!