posted by Victoria on .
if theta is an angle in standard position and B(-3,4) is a point on the terminal side of the angle, what is the value of sin theta?
r^2 = (-3)^2 + 4^2 = 25,
r = 5.
sinAr = Y/r= 4 / 5 = 0.8,
Ar = 53.1deg = reference angle.
sinAr = Y/r = 4 / 5 = 0.80,
Since the angle is in Q2,the angle
calculated is actually the ref angle
which has the same trig ratios as the
actual angle. The actual angle is:
A = 180 - Ar = 180 - 53.1 = 126.9deg.
sin126.9 = 0.8 = sin53.1.