#35

*Area of Circles

VOCABULARY

Example 1: Estimating the Area of a Circle

Estimate the area of the circle. Use 3 to approximate .

Example 2: Estimating the Area of a Circle

Estimate the area of the circle. Use 3 to approximate .

Example 3

Estimate the area of the circle. Use 3 to approximate .

20 m

Example 4: Using the Formula for the Area of a Circle

Find the area of the circle. Use for .22 7

Example 5

Find the area of the circle. Use for .22 7

3 m

Example 6

Find the area of the circle. Use for .22 7

312

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Example 7: Application

A drum head has a radius of 18 in. Find the area of the material covering the drum head. use 3.14 for .

18 in.

Example 8

The figure shows the dimensions of a standard compact disc.

What is the area of the hole in a compact disc? Use 3.14 for and round to the nearest tenth.

π

Example 9What is the area of the plastic that is used to make a compact disc? Round to the nearest square centimeter.

Example 10A circular living room has a diameter of 16 ft. Carpeting for the room costs $2.25 per square foot. How much does it cost to put wall-to-wall carpeting in the room? Use 3.14 for π.