28+Area+of+a+Circle,+Area+of+a+Sector

Area of Circle

Josh Spector, Amelia Moose, and Alex Margulies

__Area of a Circle__

The area of a circle is the number of square units inside of the circle. In the equation A = π r2, π is approximately 3.14 and r is radius. To find the complete area of a circle you multiply the squared radius by Pi.

__Area of a Circle Sector__

The area of a circle sector is part of the entire area of a circle. The area of a sector of a circle can be calculated by degrees. The section that needs to be measured will have an angle measure, which you put over 360 as a fraction. You then multiply that fraction by π r2. The fraction will divide the area to get the information you need.

__Area of Circle Examples__

Given: Radius is 4 units long Given: Diameter is 10 units long



__Area of Sector Examples__

Given: Area of sector is 37 degrees The Radius is 17 units long



__Sources__

http://www.mathgoodies.com/lessons/vol2/circle_area.html

http://math.about.com/od/formulas/ss/surfaceareavol_7.htm

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