Welcome to Circle.org - The best Information and reference guide for circle and hteir formulas.
Quick Access circles formulas:
Circumference = 2 • π • radius = π • diameter
Circle Area = π • r² = ¼ • π • d²
Sphere Surface Area = 4 • π • r² = π • d²
Sphere Volume = 4/3 • π • r³ = ( π •d³)/6
Surface Area = (2 • π • r²) + (2 • π • r • height)
Where (2 • π • r²) is the surface area of the "ends" and (2 • π • r • height) is the lateral area (the area of the "side").
Volume = π • r² • height = ¼ • π • d² • height
arc: a curved line that is part of the circumference of a circle
chord: a line segment within a circle that touches 2 points on the circle.
circumference: the distance around the circle.
diameter: the longest distance from one end of a circle to the other.
origin: the center of the circle
pi (): A number, 3.141592..., equal to (the circumference) / (the diameter) of any circle.
radius: distance from center of circle to any point on it.
sector: is like a slice of pie (a circle wedge).
tangent of circle: a line perpendicular to the radius that touches ONLY one point on the circle.
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