1. Arcs and Sectors
Circles Lesson 2

2. Do Now
1. What is the equation of the circle pictured below? 2. In triangle ABC, m∠B > m∠C > m∠A. What is the shortest side of the triangle?

3. Warming Up… What is the area of this circle?
What is the circumference of this circle?
What is the area?
What is the circumference?

4. Arcs and Sectors Notes
Minor Arc Major Arc Sector

5. Arcs and Sectors Notes Circumference Area Arc Length Sector Area
Distance around outside of circle
Space inside of the circle
C = 2πr C = πd
A = πr²
The area of a portion of the inside of the circle
The length of a portion of the outside of the circle

6. Class Example 1
A cookie cake has a diameter of 15”. What would the area of one slice be if you had to cut it in 8 equal slices?

7. Class Example 2
Find the area of the shaded sector and the arc length.

8. Class Example 3
Find the shaded area.
Given:
AB ≅ BC
AE = 16

9. Student Example 1
Find the major arc length.

10. Student Example 2
Find the area of the sector.

11. Student Example 3
Find the area of the shaded sector and the arc length.