The formula for the circumference of a circle is:
C = 2πr
The radius (r) is half of the diameter, so to find the radius just divide the diameter by two...
radius = 20 ÷ 2
radius (r) = 10 m
Plug in what you know into the formula for the circumference:
C = 2π(10)
C = 20π
The exact circumference is: 20π m
The approximate circumference is: 63 m
Hope this helped!
~Just a girl in love with Shawn Mendes