10.7 Areas of Circles and Sectors• The area of a circle is the product of pi and the

square of the radius.

2A r

Finding the Area of a Circle• The diameter of the circular region on the wrestling

mat is 32 feet. What is the area?

2A r2(16)A

256A 804.2477193

2804 .ft

Sector of a Circle• A sector of a circle is a region bounded by an arc of

the circle and the two radii to the arc’s endpoints.– You name a sector using one arc endpoint, the center of

the circle, and the other arc endpoint.

Area of a Sector of a Circle• The area of a sector of a circle is the product of the

radio measure of the arc : 360 and the area of the circle.

Finding the Area of a Sector of a Circle• What is the area of sector GPH? Leave your answer

in terms of pi.

2sec

360

mGHareaof torGPH r

272(15)

360

245 cm

Segment of a Circle

• A part of a circle bounded by an arc and the segment joining its endpoints is a segment of a circle.

• To find the area of a segment for a minor arc, draw radii to form a sector.

• The area of the segment equals the area of the sector minus the area of the triangle formed.

Finding the Area of a Segment of a Circle

• What is the area of the shaded segment shown? Round your answer to the nearest tenth.

Finding the Area of a Segment of a Circle

2sec360

mABAreaof torACB r

260(18)

360

541

2areaof ABC bh

1(18)(9 3)2

81 3

54 81 3areaofshadedsegment 29.34988788

229.3 .in

More Practice!!!!!

• Homework – Textbook p. 663 – 664 # 7 – 25 ALL.