Calculate the area of CIRCLE ?

A circle is a set of all points that are at a given distance from a center point. The diameter (d) of a circle is the length of a line that goes across the circle through its center point. The radius (r) is the distance from the center point to any point on the circle; it is also one-half the diameter.

If we were to wrap the diameter around the circle, it would require approximately 3.14 diameters to complete the circle. (This is true for any circle, no matter what size.) The value of approximately 3.14 is a number that we call pi (π). We use to do calculations with circles. It is a decimal that goes on forever, but we usually round it to 3.14.

To find the area of a circle, multiply the radius by itself, and multiply the resulting number by . The area will be expressed in square units.

The circumference (C) is the distance around the circle. You find the circumference by multiplying the diameter by . Remember that the diameter is 2 times the length of the radius, so we can also find the circumference by multiplying the radius by 2, and multiplying the result by.

Key Terms: Radius ( r ), Diameter (d), π = 3.14 units
Area (A) =( π xrxr) = (π xr2) =πr2
Circumference (C) = (2xπxr) = 2πr or dπ