$\"\"$

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Observe the figure:

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The diameter of the circle is $\"\"$ .

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Area of circle is $\"\"$ .

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ ( $\"\"$ )

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$\"\"$ (Evaluate power: $\"\"$ )

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$\"\"$ (Sum of the squres: $\"\"$ )

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$\"\"$ (Evaluate power: $\"\"$ )

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$\"\"$ (Multiply)

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$\"\"$ (Commutative property: $\"\"$ )

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Therefore, the area of the circle is $\"\"$ .

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$\"\"$

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The Area of the circle is $\"\"$ .