## Area of a Circle

### 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 = 50.24m^{2}

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 = 12.56m^{2}

### Area: Practice

00:00

What is the area of a circle whose

is cm?

cm^{2}

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