1. Chapter 11.5 Notes: Areas of Circles and Sectors Goal: You will find the areas of circles and sectors.

2. Circles Theorem 11.9 Area of a Circle: The area of a circle is times the square of the radius. Ex.1: Find the indicated measure. a. Area b. Diameter r = 2.5 cm A = 113.1 cm 2

3. Sectors A sector of a circle is the region bounded by two radii of the circle and their intercepted arc. Theorem 11.10 Area of a Sector: The ratio of the area of a sector of a circle to the area of the whole circle (Πr 2 ) is equal to the ratio of the measure of the intercepted arc to 360 o.

4. Ex.2: Find the areas of the sectors formed by Ex.3: Use the diagram to find the indicated measure. a. Area of circle D. b. Area of red sector.

5. Ex Ex.4: Use the diagram to find the area of circle V. Ex.5: Find the area of circle H.

6. Ex.6: Find the area of the figure. Ex.7: Find the area of the blue sector.

7. Ex.8: