Technical Tip / Reminder:
The formula for determining the circumference or circle diameter is:
With known radius: U=2*r*π
Or with known diameter: U=d:π
Examples:
Circle diameter 20 cm * 3.1415 (π)= 62.83 cm Circle circumference
Circle diameter 15 cm * 3.1415 (π)= 47.12 cm Circle circumference
Circle circumference 60 cm : 3.1415 (π)= 19.09 cm Circle diameter
Circle circumference 50 cm : 3.1415 (π)= 15.91 cm Circle diameter
Don't forget to add the seam allowances!