無料 online circle計算機. Enter any one value (radius, diameter, circumference, or area) と instantly calculate all other circle measurements with formulas と step-by-step solutions.
This circle計算機 のお手伝いをします find all measurements of a circle when you know any one value. Whether you have the radius, diameter, circumference, or area, enter it と the計算機 instantly computes the other three values using the fundamental formulas of circle geometry. Perfect for students, engineers, architects, と DIY enthusiasts.
The area of a circle is calculated using A = πr², where r is the radius of the circle. If you know the diameter, you can use A = π(d/2)².
First, find the radius using r = √(A/π), then calculate the circumference with C = 2πr. This計算機 does both steps automatically.
Pi (π) is a mathematical constant approximately equal to 3.14159. It represents the ratio of a circle's circumference to its diameter と appears in all circle formulas.
This計算機 is for 2D circles only. For spheres, you would need additional formulas involving volume (V = 4/3 πr³) と surface area.
はい, this計算機 uses JavaScript's built-in Math.PI constant (3.141592653589793) for maximum precision. 結果s are accurate to at least 10 decimal places.