Well, darling, the circumference of a circle is calculated using the formula C = 2πr. So, with a radius of 21 cm, you just plug that bad boy in and get C = 2 x π x 21 = 132 cm. Voilà, there you have it!
Chat with our AI personalities
Remember the circle eq'n
C = 2 pi r
pi = 3.141592... ~ 3.14
r = 21 cm
Hence
C = 2 x 3.14 X 21 cm
C = 131.88 cm
The circumference of a circle with an 8 cm radius is: 50.27 cm
The circumference of a circle with a radius of 8.5 cm is: 53.41 cm (radius x 2 x Pi = circumference).
The radius of the circle is: 9.549 cm
If the radius of a circle is 15 cm, the circumference is: 94.2 cm
The circumference of a circle with radius of 10cm is: 62.83 cm