SOLUTION: find sin theta if cos theta = 5/13 and theta terminates in QI

Algebra ->  Trigonometry-basics -> SOLUTION: find sin theta if cos theta = 5/13 and theta terminates in QI      Log On


   

Question 652320: find sin theta if cos theta = 5/13 and theta terminates in QI
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
find sin theta if cos theta = 5/13 and theta terminates in QI
----
cos = x/r, so x = 5 and r = 13
----
Solve for "y":
y^2 = r^2-x^2
y = sqrt[13^2-5^2) = sqrt[169-25] = sqrt(144) = 12
-----
Ans: sin = y/r = 12/13
==========================
Cheers,
Stan H.