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Pearson Geometry Common Core, 2011

PG

Pearson Geometry Common Core, 2011 View details

3. Surface Areas of Pyramids and Cones

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Exercise 53 Page 715

Recall the formula for finding the area of a circle?

176.7in.^2

Practice makes perfect

The area of a circle with radius r is calculated using the formula below. A=π r^2 From the description, we know that the diameter of the circle is 15 inches, which means that the radius is 15÷2=7.5 inches long. By substituting 7.5 for r in the formula, we can calculate A.

A=π r^2

r= 7.5

A=π( 7.5)^2

Calculate power

A=π * 56.25

Use a calculator

A=176.714586...

Round to 1 decimal place(s)

A≈ 176.7

The area of the circle is approximately 176.7 square inches.

Subchapter links

Lesson Check p.712

Practice and Problem-Solving Exercises p.713-715

Standardized Test Prep p.715

Mixed Review p.715