# Circles

# Circles: Piece of the Pi Quiz

Think you’ve got your head wrapped around

*? Put your knowledge to the test. Good luck — the Stickman is counting on you!***Circles**Q. A circle divides a plane into ___ regions, including the circle itself.

1

2

3

4

5

Q. In the following figure, points

*A*,*B*, and*C*are on ⊙*O*. Which of the following angles are central angles of ⊙*O*?

∠

*AOC*only∠

*OBC*only∠

*OBC*and ∠*OCB*only∠

*AOC*, ∠*AOB*, and ∠*BOC*onlyAll angles in the figure are central angles

Q. The radius of ⊙

*P*is 3 cm. What is the exact circumference of ⊙*P*? 3π cm

6π cm

9π cm

1.5π cm

cm

Q. Suppose arc

*AB*and arc*CD*are congruent. Which of the following is a true statement? Arc

*AB*and arc*CD*have the same measure, but they might not have the same length. Arc

*AB*and arc*CD*have the same length, but they might not have the same measure. Arc

*AB*and arc*CD*have the same length and the same measure, but they might not have the same radius. Arc

*AB*and arc*CD*have the same length, the same measure, and the same radius. None of the above

Q. Arc

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

36π cm

2π°

36π°

360°

Q. 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°

90°

60°

120°

240°

Q. 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*?

24°

156°

204°

km

km

Q. Suppose arc

*LM*and arc*PQ*have the same length. Which of the following must be true? Arc

*LM*and arc*PQ*have the same measure. Arc

*LM*and arc*PQ*have the same radius. Arc

*LM*and arc*PQ*are congruent. Arc

*LM*and arc*PQ*are the same arc. None of the above

Q. The circumference of ⊙

*O*is exactly 56 m. Which of the following is closest to the radius of ⊙*O*?17 m

4 m

178 m

18 m

9 m

Q. A semicircle always _____.

is a major arc

is a minor arc

is an arc with measure 180°

subtends a central angle that is acute

has an arc length equal to its arc measure