Circle Calculator
Find circumference, area, arc length, sector area and chord length from a radius or diameter, with steps. Try “arc length of a sector with r = 6 and angle 75°”.
Try an example:
What you can do with the Circle Calculator
Circumference, arc, sector, chord and tangent problems.
Enter your values or describe the problem in the calculator above. Review the result and the explanation before using it in homework, study or practical calculations.
Example input
e.g. arc length of a sector with r = 6 and angle 75 degrees
How the Circle Calculator works
- Get the radius (half the diameter).
- Use C = 2πr and A = πr², or arc = (θ ÷ 360) × 2πr for an angle in degrees.
- Substitute, simplify and give your answer in terms of π or as a decimal.
Frequently asked questions
What is the formula for arc length?
Arc length = (θ ÷ 360°) × 2πr when θ is in degrees, or rθ when θ is in radians.
How do I find the area of a sector?
Sector area = (θ ÷ 360°) × πr², or ½r²θ in radians.
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Math Solver can make mistakes. Please double-check important steps and calculations.