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A circle has an area of 49pi square units. What is the length of the circle's diameter?

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seedrasoso | Student, Grade 10 | (Level 2) Honors

Posted June 22, 2010 at 7:30 AM via web

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A circle has an area of 49pi square units. What is the length of the circle's diameter?

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hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted June 22, 2010 at 7:32 AM (Answer #1)

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The area of the circle= pi*r^2

==> pi*r^2= 49*pi

==> r^2 = 49

==> r= 7

The diameter = 2 * radius = 1*7 = 14 units

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brianevery | High School Teacher | (Level 2) Adjunct Educator

Posted June 22, 2010 at 7:34 AM (Answer #2)

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The area of a circle is found by using the formula A=PiR^2 so a circle with an area of 49pi, 49 must be the radius squared (R^2)

The sqrt(49)=7 so the radius should be 7, the diameter is twice the length of the radius, or 2*7=14

14 units is the length of the diameter.

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