Semicircle

In geometry a semicircle is simply half a circle or a closed shape consisting of half a circle. It is a one-dimensional locus of points that forms half of a circle. The arc that forms a semicircle always measures 180 ° or π
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Area of a semicircle

Since a semicircle is half a circle that must mean that its area if also half the area of a circle. The area of a circle is πR ² where R is the radius. Therefore the formula of the area of a semicircle is;
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…where;

• R is the radius of the semicircle
• π is Pi, approximately 3.142

Perimeter of a semicircle

In this case the perimeter of the semicircle is NOT half the perimeter of a circle. The perimeter is the curve plus the diameter of the semicircle. Therefore the perimeter of the semicircle is;
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…where;

• R is the radius of the semicircle
• π is Pi, approximately 3.142

We can further simplify it to;
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