# 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
cm
Diameter
ft
in
Diameter
meters
Diameter
yards
Units
Area of a 21cm diameter circle
 346.36 square centimeters 0.034636 square meters 53.686 square inches 0.37282 square feet 0.041424 square yards
results may be rounded

#### Area of a Circle Formula

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

Area = π * (Diameter / 2)2

#### Diameter of a Circle

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