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Smmall additions about areas
The distance around the circle, or [[circumference]], is given by:
The distance around the circle, or [[circumference]], is given by:
:<math>C = 2\pi*r</math>
:<math>C = 2\pi r</math>
The area inside the circle is calculated using the formula:
The area inside the circle is calculated using the formula:
:<math>A = \pi*r^2</math>
:<math>A = \pi r^2</math>
This can be easily derived from the area of an [[ellipse]]. For an [[ellipse]] with major and minor axis <math>a</math> and <math>b</math> respectively, the area is <math>\pi ab</math>. Setting the major an minor axis equal to each other give the formula for a circle.
A circle is a [[conic section]], the intersection of a plane with a cone such that the plane is perpendicular to the axis of the cone.
A circle is a [[conic section]], the intersection of a plane with a cone such that the plane is perpendicular to the axis of the cone.
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