Use a Graphing Calculator to Make a Conjecture as to Whether

Multiple Choice

Use a graphing calculator to make a conjecture as to whether each equation is an identity.
-Find $\sin \theta$ if $\cos \theta = \frac { 2 } { 3 }$ and $\theta$ is in quadrant IV.

A) $- \frac { \sqrt { 5 } } { 3 }$
B) $\frac { 5 } { 4 }$
C) $- \frac { 3 } { 2 }$
D) $\frac { 3 \sqrt { 7 } } { 7 }$