Area of a Circle

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Area: Learn

Area is the space within a shape. The units of area are the squares of the units of length (that is, if a shape's sides are measured in meters, then the shape's area is measured in square meters).

For a circle, we will need to incorporate the constant pi, which we will approximate as the decimal 3.14.

To find the area of a circle, multiply pi (3.14) by the square of radius. In other words, multiply pi times the radius times the radius.

For example, if a circle has a radius of 4m, the area is 3.14*4*4 = 50.24m2

If you are given a diameter instead of a radius, just remember that the radius is half of the diameter.

For example, if a circle has a diameter of 4m, then the radius is 2m, and the area is 3.14*2*2 = 12.56m2

Area: Practice

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What is the area of a circle whose
is cm?

cm2

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