Circumference Calculator
Calculate circumference, diameter, radius, and area of a circle with step-by-step solutions
Circle Calculator
Enter the radius in cm
Circle Properties
Example Calculations
Example 1: From Radius
Given: Radius = 5 cm
Diameter: d = 2r = 2 × 5 = 10 cm
Circumference: C = 2πr = 2π × 5 ≈ 31.42 cm
Area: A = πr² = π × 5² ≈ 78.54 cm²
Example 2: From Circumference
Given: Circumference = 44 cm
Radius: r = C/(2π) = 44/(2π) ≈ 7.00 cm
Diameter: d = 2r = 2 × 7.00 ≈ 14.01 cm
Area: A = πr² = π × 7.00² ≈ 154.06 cm²
Circle Properties
Radius
Distance from center to edge
Diameter
Distance across through center
Circumference
Distance around the circle
Area
Space inside the circle
Key Formulas
Understanding Circumference and Circle Properties
What is Circumference?
The circumference of a circle is the length of the circle's boundary or perimeter. It represents the distance you would travel if you walked around the edge of a perfect circle.
Key Circle Relationships
- •The diameter is always twice the radius (d = 2r)
- •The circumference is π times the diameter (C = πd)
- •The area increases with the square of the radius (A = πr²)
- •π (pi) is approximately 3.14159 (an irrational number)
Circumference Formulas
From Radius
C = 2πr
Multiply radius by 2π (about 6.283)
From Diameter
C = πd
Multiply diameter by π (about 3.14159)
From Area
C = 2√(πA)
Take square root of area times π, then multiply by 2
Real-World Applications
Engineering
Calculate pipe circumferences, wheel perimeters, and circular component dimensions in mechanical design.
Construction
Determine materials needed for circular structures, landscaping features, and architectural elements.
Science
Analyze circular motion, calculate orbital circumferences, and determine particle path lengths.