12-09-2005, 06:22 AM
Quote:The diameter of a circle is the distance from a point on the circle to a point Radians away, and is the maximum distance from one point on a circle to another. The diameter of a sphere is the maximum distance between two antipodal points on the surface of the sphere.
If is the radius of a circle or sphere, then . The ratio of the circumference of a circle or great circle of a sphere to the diameter is pi
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basically this: the radius is the line from the center of a circle or shpere to the outer edge.....the diameter is from one edge to the other, or 2x the radius. The circumference, if I remember my high school geometry, is the total distance around the outside of the circle/sphere....the formula is pi*diameter.