www.reference.com/article/area-semicircle-ac74ac6fb847ce40

To find the area of a semicircle, use the formula 1/2(pi x r^2). You need the value of "r," or radius of the circle, and pi.

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The area of a semicircle is (?*R*R)/2. This means the radius of the semicircle is squared, multiplied by the constant pi, then divided by 2.

www.reference.com/article/determine-circumference-semicircle-e44c79f6976ca3d2

The perimeter of a semicircle is 1/2 of the circumference of the corresponding complete circle plus the diameter of the circle. The distance around the outside of a semicircle is generally called its perimeter.

www.reference.com/article/area-circle-87e7360e7b547274

Find the area of a circle using the equation A=?r^2. The area is equal to the radius, which is the distance from the center of the circle to its edge, times itself, times pi (approximately 3.1415).

www.reference.com/article/area-c17efe71aeaa3d8

Different formulas exist for finding the areas of different types of polygons. To find the area of any polygon, first identify which formula to use and then replace the variables with the known dimensions of the polygon.

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The area of a rectangle is calculated from its width and height. Since a square is also a rectangle, the area of such polygons is also determined using the formula "area = width x height."

www.reference.com/article/area-square-7e94b3fba4c5e1ad

The area of a square or rectangle is equal to its width times its height. The sides of a perfect square are all equal, so the formula for a square is also area = x (squared), where "x" is the length of one side.