How To Convert The Area Of A Circle To Square Feet

Though it may seem strange to say, circles are measured in square units. The area of a circle requires squaring its radius, which is a straight line from its origin, or center coordinates, to its rim, or circumference. Multiplying a unit of measurement to itself results in that unit being square; when multiplying a foot by a foot, the result is a square foot. Given that a circle's area is in square units, it can be converted to square feet from other square measurements.

Step 1

Measure the length of the diameter. The diameter is a straight line that travels from one point on the circle's circumference, through its origin, and to a second point on the circumference. For this example, the diameter is measured at 8 yards.

Step 2

Halve the length of the diameter to calculate the length of its radius. For this example, half of 8 yards is 4 yards.

Step 3

Square the length of the radius. For this example, 4 yards squared becomes 16 square yards.

Step 4

Multiply the amount of the radius squared by pi to calculate the area in square yards. Pi is a mathematical constant that begins as the number 3.14 and never terminates. For this example, 16 square yards multiplied by pi equals 50.265 square yards.

Step 5

Multiply the amount in square yards by 9 to convert the area to square footage. For this example, the amount of 50.265 in square yards multiplied by 9 converts to 452.385. Click on the Metric Conversion Chart link (see resources) to see how to convert other common square amounts to square meters. For example, 1 square foot equals 144 square inches and 1 square meter equals 10.764 square feet.