find the circumference of a circle that has a diameter of three inches. give exact value

## find the circumferance of a circle that has a diameter of three inches. Give exact value

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# 3 Answers

circumference=pi*diameter

C=(pi)(d)

=3.14159*3

=9.42477 in

this is not an exact value because pi is an irrational number, a non-ending, non-repeating decimal,

in other words, it cannot be written as a simple fraction a/b

Circumference = pi(D) = (pi)(3) = 3pi or 3π. That's the EXACT value.

Approximate value would be using 3.14 for pi

3.14

x 3

====

9.42 in.

Approximate value would be using 3.14 for pi

3.14

x 3

====

9.42 in.

What is wrong with 3π as an exact answer? I admit it is not possible to write it as a decimal, but that was not the question.

## Comments

exactmay have different meanings for different people. Maybe to the student exact meant 3 times some approximate value of pi. Or maybe 3pi is what the student was looking for. Anyway, we gave him both answers to choose from.Comment