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Page 1: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 1

March 07, 2012

Bellwork

about 56.5 cm. 8.64 cm

100.53 cm

7.64 ft

Page 2: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 2

March 07, 2012

A circle has an area of ≈ 38.485 in2. What is the circumference of the circle?

11.5 Areas of Circles & Sectors

Area of Circle = πr2 (fuzzy wuzzy)

4.2 m

Page 3: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 3

March 07, 2012

20 in

Find the area of the shaded region.

10 cm

Page 4: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 4

March 07, 2012

Sector of a Circle:region bounded by 2 radii of a circle & the included arc

Formula for the Area of a Sector:“portion of the circle times the area of the circle”

Asector = x360

πr2

r = 3 cm

120 o

r = 6cm

60o

Page 5: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 5

March 07, 2012

Segment of a Circle:region bounded by a chord of a circle & the included arc

r = 8 cm

Page 6: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 6

March 07, 2012

Annulus:region bounded by two concentric circles

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11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 7

March 07, 2012

R = 12cmr = 9 cm

r  

60o

R

The shaded area is 12π cm2.  Find r.

r

120o

Page 8: 11.5 notes

11.5 Area of Circles & Sectors

HW pg. 758 #3­31 odds 8

March 07, 2012

11.5 HW pg. 758 #3-31 odds