Question #190b0

1 Answer
Jun 17, 2017

1.23095942 rad=70.5287794°

Explanation:

For values not on the unit circle, it's easiest to use a calculator.

Take the inverse cosine of both sides to "undo" the cosine function.

costheta=(1/3)
cos^-1(costheta)=cos^-1(1/3)
theta=cos^-1(1/3)

theta=1.23095942 rad=70.5287794°

[can be expressed in radians or degrees]