Copyright © by Holt, Rinehart and Winston. 22 Holt Geometry

All rights reserved.

Name Date Class

LESSON Reteach

Sector Area and Arc Length11-3

Sector of a Circle

A sector of a circle is a region bounded by two

radii of the circle and their intercepted arc.

The area of a sector of a circle is given by the

formula A 5 pr2 _ m° ____

360° +.

Segment of a Circle

A segment of a circle is a region bounded by an arc and

its chord.

area of

segment ABC5

area of sector

ABC2 area of nABC

Find the area of each sector. Give your answer in terms of p and

rounded to the nearest hundredth.

1. sector CDE 2. sector QRS

7p cm2; 21.99 cm

2 27p in2; 84.82 in

2

Find the area of each segment to the nearest hundredth.

3. 4.

1.14 in2 5.80 m

2

sector ABC

segment ABC

Copyright © by Holt, Rinehart and Winston. 23 Holt Geometry

All rights reserved.

Name Date Class

LESSON

Arc Length

Arc length is the distance along an arc measured in linear units.

The arc length of a circle is given by the formula L 5 2pr _ m° ____ 360°

+.

Find the arc length of C

JK .

L 5 2p r _ m ° ____ 360°

+ Formula for arc length

5 2p (9 cm)_ 84° ____ 360°

+ Substitute 9 cm for r and 84° for m°.

5 21 ___ 5

p cm Simplify.

< 13.19 cm Round to the nearest hundredth.

Find each arc length. Give your answer in terms of p and rounded to

the nearest hundredth.

5. C

AB 6. C

WX

11p in.; 34.56 in. 7p cm; 21.99 cm

7. C

QR 8. C

ST

4p in.; 12.57 in. 9 ___ 10

p or 0.9p mm; 2.83 mm

11-3

Reteach

Sector Area and Arc Length continued