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

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- anonymousLv 77 years agoFavorite Answer
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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