How we worked it out
Updated as you change the numbers.
- Area = πr². Circumference = 2πr = πd.
Method and assumptions
All circle measurements follow from the radius: diameter 2r, circumference 2πr and area πr². Area and lengths can be converted to any unit in the answer.
Questions
What is the area of a circle with a 5 in radius?
78.54 square inches; the circumference is 31.42 in.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.