Use the Given Information to Find the Exact Value of the Trigonometric

Multiple Choice

Use the given information to find the exact value of the trigonometric function.
- $\cos \theta = - \frac { 3 } { 5 } , \theta$ lies in quadrant III Find $\cos \frac { \theta } { 2 }$ .

A) $- \frac { \sqrt { 5 } } { 5 }$
B) $\frac { \sqrt { 5 } } { 5 }$
C) $- \frac { \sqrt { 30 } } { 10 }$
D) $\frac { \sqrt { 30 } } { 10 }$