Help solving a Pythagorean theorem problem

[Dmoney1578]

Can any one help me solve (use the Pythagorean theorem to find sin(t) when cos(t)=1/2 and - ?/2<t<0)

 

[skeeter]

\(\displaystyle \sin^2{t} + \cos^2{t} = 1\)

don't forget the sign of sin(t) in the indicated quadrant.