1. 
A circle divides a plane into ___ regions, including the circle itself.1

2. 
In the following figure, points A, B, and C are on ⊙O. Which of the following angles are central angles of ⊙O? ∠OBC only

3. 
The radius of ⊙P is 3 cm. What is the exact circumference of ⊙P? 6π cm

4. 
Suppose arc AB and arc CD are congruent. Which of the following is a true statement? Arc AB and arc CD have the same length, the same measure, and the same radius.

5. 
Arc ST has measure 60° and radius 6 cm. What is the exact length of arc ST? 2π cm

6. 
In the figure below, points A, B, and C are on ⊙O. If m∠AOB = 30° and ∠BOC is a right angle, what is the measure of arc ABC? 30°

7. 
In the figure below, points A, B, C, and D are points on ⊙O and lines AC and BD intersect at O. m∠AOB = 24°. Distance OB is 5 km. What is the exact measure of arc BC? 156°

8. 
Suppose arc LM and arc PQ have the same length. Which of the following must be true? Arc LM and arc PQ are congruent.

9. 
The circumference of ⊙O is exactly 56 m. Which of the following is closest to the radius of ⊙O?9 m

10. 
A semicircle always _____. is an arc with measure 180°
