# Diameter is 7/22 cm. What is the circumference?

We are given a diameter of 7/22 centimeters.

A diameter is the length of a straight line segment which passes through the center of a circle and has its endpoints on the circle itself.

The circumference of a circle is simply the length of one complete revolution of the circle.

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We are given a diameter of 7/22 centimeters.

A diameter is the length of a straight line segment which passes through the center of a circle and has its endpoints on the circle itself.

The circumference of a circle is simply the length of one complete revolution of the circle.

The circumference of a circle is equal to the diameter (D) times pi (`D*pi` ). The circumference of a circle is also often stated as `2*pi*R`  where R is the radius. However, the diameter is simply twice the length of the radius, so we can see the two statements for circumference are equivalent.

`2*R=D` thus

`2*R*pi=D*pi`

So the circumference of our circle is:

`D*pi=(7/22)*pi=0.999 ` centimeters

Recall that the definition of pi is the circumference of a circle divided by its diameter.

Pi = circumference / diameter = approximately 3.14

Approved by eNotes Editorial Team