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McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

1. Circles and Circumference

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Exercise 57 Page 723

Use the formula for the circumference of a circle.

J

Practice makes perfect

We are given that Bill is planning a circular vegetable garden with a fence around the border. We know that he can use up to 50 feet of fence. To find the possible radius of the garden let's recall the formula for the circumference of a circle. C=2π r By substituting 50 for C we can find the maximum radius.

C=2π r

r= 50

50=2π r

.LHS /2π.=.RHS /2π.

50/2π=r

Rearrange equation

r=50/2π

Use a calculator

r=7.9577...

Round to 2 decimal place(s)

r≈ 7.96

The radius of the fence can be at least equal to 7.96 feet. Therefore, J is the correct answer.

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Exercises p.719-723