How do you find the circumference and area of a circle with a diameter of 7cm?

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Answer 1 · 2018-03-10T17:37:29

See a solution process below:

The diameter of a circle is twice its radius or: #d = 2r#

The formula for the circumference of a circle is: #C = 2pir#

Or: #C = 2rpi#

Or: #C = dpi#

Substituting the diameter of the circle from the problem gives:

#C = 7"cm" * pi#

#C = 7pi"cm"#

If you approximate #pi# with #3.14# then:

#C ~= 7 * 3.14"cm"#

#C ~= 21.98"cm"#