Section 8.6

 If you cut a slice of pizza, each slide would probably be a sector of a circle. The sector is the region between two radii and an arc of the circle.

 If you could make only one straight cut with your knife, your slice would be a segment of a circle. A segment of a circle is the region between a chord and an arc of the circle

 If you don’t like the crust, you’d cut out the center of the pizza; The crust shape that remains is called an annulus. An annulus is the region between two concentric circles.

If the larger circle has a radius of R and the smaller circle has a radius of r then the area of the annulus would be

If the larger circle has a radius of 9 and the smaller circle has a radius of 6 then the area of the annulus would be

Area of a Sector of a Circle

What fraction of the circle is shaded in? What is the area of the whole circle? How much area would in our sector?

Area of a Segment of a Circle

What fraction of the circle are we thinking about? What is the area of the sector? What is the area of the triangle? What is the area of the segment?

 Find the area of the shaded sector.

 The shaded area is 14π sq. cm., and the radius is 6 cm. Find x.