Area of a 21 Centimeter Circle

What is the area of a circle with a DIAMETER of 21 cm (radius of 10.5 cm)? How big is a 21 centimeter circle?

Diameter

meters

Diameter

yards

Units

Area of a 21cm diameter circle

results may be rounded

The area of a circle is pi times the square of its radius. The radius is half the diameter.

Area = π * (Diameter / 2)²

The diameter of a circle is the distance from one edge to the other, passing through the center. It is twice the radius.

Circle Area by Diameter

results may be rounded

Diameter	cm²	in²	ft²
21.0 cm	346.4	53.69	0.3728
21.1 cm	349.7	54.20	0.3764
21.2 cm	353.0	54.71	0.3800
21.3 cm	356.3	55.23	0.3835
21.4 cm	359.7	55.75	0.3872
21.5 cm	363.1	56.27	0.3908
21.6 cm	366.4	56.80	0.3944
21.7 cm	369.8	57.32	0.3981
21.8 cm	373.3	57.85	0.4018
21.9 cm	376.7	58.39	0.4055