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Pearson Geometry Common Core, 2011

PG

Pearson Geometry Common Core, 2011 View details

Chapter Review

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Exercise 40 Page 74

Use that C=2π r to find the circumference.

Circumference: 6π in
Area: 9π in^2

Practice makes perfect

The circumference of a circle can be found by multiplying twice the radius by π. C= 2 π r We know that this circle has a radius of 3 inches, so we can substitute 3 for r in the formula.

P=2π r

r= 3

P=2*π* 3

Multiply

P=6π

The circumference is 6π inches. Now we can find the area. To find the area of a circle, we use the following formula. A=π r^2 Let's substitute the radius into this formula this time.

A=π r^2

r= 3

A=π* 3^2

Calculate power

A=π*9

Multiply

A=9π

The area is 9 π in^2.

Subchapter links

Exercises p.70-74