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Calculate the area of a semicircle with a diameter of 25 cm.?

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  • 7 years ago
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    Calculate the area of a circle with diameter 25 cm , and the semicircle will have area one-half of that.

    However, to do the area of a circle with diameter 25 cm, you need to use the radius of the circle, not the diameter. The radius is (1/2) the diameter, or 12.5 cm .

    The area of the entire circle is

    A = πr²

    = π * (12.5 cm)²

    = π * 156.25 cm²

    The area of the semicircle is half of that, or

    [ (π * 156.25 cm²) / 2 ]

    = π * 78.125 cm²

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    That's the exact answer. Using a calculator to approximate the area of the semicirce, it is

    A(semicircle) ≃ 245.44 cm²

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