Circle Area and CircumferenceDate: 03/16/2002 at 19:21:22 From: Briddy Subject: Area and Circumference I need help with area and circumference. Are radius and diameter the same thing as area and circumference? Date: 03/17/2002 at 11:18:14 From: Doctor Sarah Subject: Re: Area and Circumference Hi Briddy - thanks for writing to Dr. Math. The circumference of a circle is the distance around it. It is measured in linear units (inches, feet, etc.). The formula for the circumference of a circle is: C = pi*d (pi times the diameter) The diameter of a circle is a chord that passes through the center of the circle. (A chord is a line segment with endpoints on the circumference of a circle.) The area of the circle is the number of square units needed to cover its surface. It is measured in square inches, square feet, etc. The formula for the area of a circle is: A = pi * r^2 (pi times the radius squared) The radius of a circle is a line segment with one endpoint at the center of the circle and the other endpoint on the circumference of the circle. It is exactly half the diameter of the circle. Does this help? - Doctor Sarah, The Math Forum http://mathforum.org/dr.math/ |
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