# Math Help - Trig help

1. ## Trig help

Can someone please help me find sinA if cosA=(-3/5) and A is greater than 90 degrees, but less than 180 degrees. I'm stuck. Thankyou!

2. Use sin^2(a)+cos^2(a)=1, and the fact that sin(a) is positive since is between 90 and 180.