How to Determine the Area of a Circle
The radius of the circle, that is, the distance from the center of the circle to any point on the circumference of the circle, helps unambiguously determine the circle area. The International System of Units (SI) defines square meters as a unit of area, but other units, such as square feet and square inches, are widely used in the U.S. and in some other countries.
Other People Are Reading
Instructions
-
-
1
Measure or obtain elsewhere the radius of a circle. If you know the circle diameter, divide the value by two to compute the radius.
-
2
Retrieve the mathematical constant number "pi" with the desired accuracy; the pi value rounded to the third decimal point, "3.142," is sufficient for most calculations.
-
-
3
Raise the radius to the power of "2," and multiply by the constant pi to determine the area of the circle. For example, if the circle radius is 2.6 inches, the area will be 2.6 x 2.6 x 3.142 = 21.24 square inches.
-
4
Multiply the circle area in square inches by the factor "6.4516" to convert it to square centimeters. In our example, the area of 21.24 square inches corresponds to 21.24 x 6.4516 = 137.03 square centimeters.
-
5
Multiply the circle area in square inches by the factor "0.00694 " to convert it to square feet. In our example, 21.24 square inches will be converted to 21.24 x 0.00694 = 0.15 square feet.
-
1
