Circumference to Diameter Calculator
Convert between circumference and diameter of a circle with step-by-step solutions
Calculate Circle Measurements
The distance around the circle
Formula Used
d = c/π
Where:
- • d = diameter
- • c = circumference
- • π ≈ 3.14159...
Example Calculation
Example 1: Find Diameter from Circumference
Given: Circumference = 31.416 cm
Formula: d = c/π
Calculation: d = 31.416/π = 31.416/3.14159 ≈ 10 cm
Result: Diameter = 10 cm
Example 2: Find Circumference from Diameter
Given: Diameter = 6 feet
Formula: c = π × d
Calculation: c = π × 6 = 3.14159 × 6 ≈ 18.85 feet
Result: Circumference = 18.85 feet
Circle Properties
Pi (π)
≈ 3.14159265...
Ratio of circumference to diameter
Circumference
Distance around the circle
Formula: C = π × d
Diameter
Distance across through center
Formula: d = c/π
Radius
Distance from center to edge
Formula: r = d/2
Quick Reference
π (pi) is approximately 3.14159
Diameter = 2 × radius
Circumference = π × diameter
Area = π × radius²
All circles have the same π ratio
Understanding Circumference and Diameter
What is Circumference?
The circumference is the perimeter of a circle - the distance around its edge. It represents the length you would measure if you wrapped a string around the circle and then straightened it out.
What is Diameter?
The diameter is the distance across a circle, passing through its center point. It's the longest possible straight line that can be drawn within the circle, connecting two points on the circumference.
The Relationship
The ratio between circumference and diameter is always π (pi), regardless of the circle's size. This mathematical constant is approximately 3.14159 and is fundamental to all circle calculations.
Key Formulas
c = π × d
Circumference from diameter
d = c/π
Diameter from circumference
r = d/2
Radius from diameter
Did you know? The symbol π (pi) was first used in mathematics in 1706, but the concept has been known since ancient times.