Answer:
Here's what I get.
Step-by-step explanation:
9. (6, -8)
The reference angle θ is in the fourth quadrant.
∆AOB is a right triangle.
OB² = OA² + AB² = 6² + (-8)² = 36 + 64 = 100
OB = √100 = 10

10. cot θ = -(√3)/2
The reference angle θ is in the second quadrant.
∆AOB is a right triangle.
OB² = OA² + AB² = (-√3)² + (2)² = 3 + 4 = 7
OB = √7
