$\"\"$

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The area ( $\"\"$ ) of a circle is $\"\"$ .

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The circumference ( $\"\"$ ) of a circle is $\"\"$ .

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Consider $\"\"$ .

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Divide each side by $\"\"$ .

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$\"\"$ .

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Substitute $\"\"$ in area formula. \ \

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$\"\"$

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$\"\"$ .

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$\"\"$

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The area of a circle is $\"\"$ .