LESSON Today: Assignment 11.3 Instruction 16 30° 20 Warm-up: Find the area. 160 u 2

LESSON 11.3 Areas of Circles and Sectors Objective: 1.Find areas of circles. 2.Find areas of sectors of circles. 3.Find areas of composites. Vocabulary: sector of a circle, segment of a circle, composite

LESSON Vocabulary sector: a region of a circle bounded by 2 radii and an arc of the circle. segment of a circle: a region of a circle bounded by a chord of the circle and its corresponding arc. A B C D A B C D

LESSON Concept 1 Find the area of a circle with a radius of 8 p. A = 64 π p 2

LESSON Example 1 MANUFACTURING An outdoor accessories company manufactures circular covers for outdoor umbrellas. If the cover is 8 inches longer than the umbrella on each side, find the area of the cover in square inches. Answer:The area of the cover is about 6082 square inches.

LESSON Example 2 A.3.8 in. B.4.5 in. C.5.7 in. D.7.6 in. ALGEBRA Find the radius of a circle with an area of 45 square inches.

LESSON The green portion of  C is arc AB written AB. mAB = 90° sector ACB of  C A B C Find the length of AB Find the area of sector ACB D (Circumference of  C) (area of  C)

LESSON Concept 2 Find the measure of the sector that has a central angle of 50° and a radius of 12’. A = 20π ft 2

LESSON If m  DCG = 120° and DC = 24, find the length of DG and the area of sector DCG. length of DG = 16π u area of sector DCG = 192π u 2 D G C

LESSON Example 3 PIE A pie has a diameter of 9 inches and is cut into 10 congruent slices. What is the area of one slice to the nearest hundredth? Answer:The area of one slice of pie is about 6.36 square inches.

LESSON Area of a circle. A = πr 2 Area of a sector: Area of sector ACB = Area of a segment. (Area of  C) A B C D

LESSON Find the area of: a segment of a circle whose chord is 12” and the measure of the intercepted arc is 120°. the checkered region. 6’

LESSON Find the area of speckled regions: 3”

LESSON Assignment Due tomorrow: 11.3 P. 803 #19-29 odd, odd, 40-42, 46