1. Central and Inscribed Angles
Circles Lesson 3

2. Do Now
3. If a pie with a 9” diameter is split equally between 2 people, what is the area of pie that each person will receive? 4. The circumference of a circle is 12π. What is the arc length of an arc created with a 90° angle?

3. Central and Inscribed Angles Notes
Central Angle Inscribed Angle
An angle whose vertex is the center of the circle.
An angle whose vertex is on the edge of the circle.

4. Central and Inscribed Angles Notes
Central Angles
Inscribed Angles
Arc = Angle x 2
Angle = Arc
Angle = Arc ÷ 2
What is the degree measure of arc CE?
What is the degree measure of ∠CBE?

5. Central and Inscribed Angle Notes
What is the measure of ∠ABC?
The arc intercepted by a diameter is always 180°.
If an angle intercepts a diameter, that angle is 90°.

6. Class Example 1
Find the measure of x.

7. Class Example 2
Find the measure of arc SR.

8. Class Example 3
Find x.

9. Class Example 4
Find x.

10. Student Example 1
Find the measure of ∠WYX.

11. Student Example 2
Solve for x.

12. Student Example 3
Find the measure of arc KL.