Yuánzhōu de chángdù děngyú zhíjìng chéng yǐ yuánzhōulǜ.
The circumference equals the diameter times pi.
Tips
usage
圆周 is the math term for the boundary of a circle. The famous derivative 圆周率 means pi (π) - literally circle-circumference-rate. For everyday round shapes use 圆 or 圆圈 instead.
