Math
posted by Quinn .
LaQuisha has a sprinkler that waters a circular area. The diameter of the area that the sprinkler waters is 20 feet. The actual sprinkler is located at the origin of the coordinate plane. Write an equation that describes the circumference of the circular area that the sprinkler waters.
How would I do this problem? If you could explain this clearly, it would be much appreciated. Thanks :)

Don't we just want the circumference of a circle with a radius of 10 ?
C = 2πr
C = 20π