WEBVTT

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Here is the problem: A circle has area 100. Find its radius, diameter, circumference and area.

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Find the radius, diameter, circumference and area of a circle from any one of them.

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Radius from the area.

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Diameter.

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Circumference.

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So the answer is r equals 5.641895835, d equals 11.28379167, C equals 35.44907702, A equals 100.

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Every measurement of a circle follows from its radius. The circumference grows in proportion to the radius and the area in proportion to its square.

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C/d equals 3.141592654 equals pi.

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A equals C times r/2 equals 100.