Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
5. Volumes of Pyramids and Cones
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Exercise 46 Page 732

Do you remember the formula for the circumference of a circle?

13cm

Practice makes perfect
The circumference C of a circle with radius r is calculated using the formula below. C=2π r From the exercise, we know that the radius of the circle is 2cm. By substituting 2 for r in the formula, we can calculate the circumference C.
C=2π r
C=2π( 2)
C=2(2)π
C=4π
C=12.566371...
C≈ 13
The circumference of the circle is approximately 13cm.