1. Lesson 8-2: Formulas 1 Lesson 8-2 Formulas Circumference Arc Length Area Sector

2. Lesson 8-2: Formulas 2 Central Angle A central angle is an angle whose vertex is at the center of the circle. The measure of a minor arc is the measure of its central angle. The measure of a major arc is 360 minus the measure of its central angle. The arc measure is written as

3. Lesson 8-2: Formulas 3 Inscribed Angle An inscribed angle is an angle whose vertex is on the circle. The measure of an inscribed angle is ½ the measure of its intercepted arc.

4. Lesson 8-2: Formulas 4 CIRCUMFERENCE: Circumference is the distance around the circle. Formula:Or Example:Find the circumference of the following circle. 3 cm cm where

5. Lesson 8-2: Formulas 5 Arc Length Arc length is the distance around an arc. The circumference multiplied by the ratio of the center angle and 360°. Formula: Example: 2 cm 72  B C A Arc Length

6. Lesson 8-2: Formulas 6 Area of a Circle Area of a circle is the number of unit squares that can fit into a circle. Example:Find the area of the following circle. 3 cm Formula:

7. Lesson 8-2: Formulas 7 Area of a Sector Area of a sector is the area of a section of the circle. The area multiplied by the ratio of the center angle and 360° Formula: Example: 65° Sector