105 32 1 2 3 4 52.5 16 36.5 105 warm-up find the measures of angles 1 – 4

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105 32 1 2 3 4 52.5 16 36.5 105 Warm-up Find the measures of angles 1 – 4.

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Page 1: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

10532

1

23

4

52.5

16

36.5

105

Warm-up Find the measures of angles 1 – 4.

Page 2: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

Homework Review

1) D 1) C

2) A 2) B

3) B 3) A

4) A 4) C

5) A 5) A

6) C

7) D

8) B

Page 4: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

GPS GeometryDay 44 (10-12-12)

UNIT QUESTION: What special properties are found with the parts of a circle?Standard: MM2G1, MM2G2

Today’s Question:How do we the area of a sector using proportions?Standard: MM2G3.b

Page 5: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

1) Find the circumference and area of a circle with a diameter of 10 in.

2) What would be the radius of a circle if it’s area is ?

C = 31.42 in., A = 78.54 in.2

radius = 8

64

Page 6: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4
Page 7: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

A = r2

ANSWERS WILL BE IN SQUARE UNITS

6.8

Page 8: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

Find the area.

Page 9: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

If S has a circumference of 10 inches, find the area of the circle to the nearest hundredth.

C = 2r10 = 2r

5 = r

A = r2

A = 52A = 25A =

in2

Page 10: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

Find the area of the shaded region.

188.49in2

8 in

2 in

A = 22A = 82

A = 4

A = 12.57in2

A = 64

A = 201.06in2

A shaded = A – A= 201.06 - 12.57 =

Page 11: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

SECTOR: region bounded by two radii of the circle and their

intercepted arcR

O

Q

Area of a Sector

2

sec

360

Area of tor RQ mRQ

r

Page 12: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

60°

120 °

6 cm

7 cm

Q

R

Q

R

218.85cm

251.31cm

2

60

(6) 360

Area

2

sec

360

Area of tor QR mQR

r

2

sec

360

Area of tor QR mQR

r

2

120

(7) 360

Area

Page 13: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

A SEGMENT is a region bounded by a chord and its intercepted

arc

A segment is a minor segment if the

intercepted arc is less than 180

degrees

Area of minor segment =

(Area of sector) – (Area of triangle)

Page 14: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4

Area of minor segment =

(Area of sector) – (Area of triangle)

12 yd

2 1

*360 2

mRQr b h

R

Q290 1

(12) (12)*(12)360 2

113.10 72

241.10yd

Page 15: 105  32  1 2 3 4 52.5  16  36.5  105  Warm-up Find the measures of angles 1 – 4