What is the slope of the terminal ray?

Answer:
-1.52
-0.990 radians
No
2.15 radians
Step-by-step explanation:
The slope is equal to the y-coordinate/x-coordinate = -32/21 = -1.52
Then, tan^-1(m)=tan^-1(-32/21)=-0.990 radians
This does not give the correct value of theta, however.
The correct value of theta is tan^-1(-32/21)+pi=2.15 radians