Posted by afn03488 on 04/26/06 15:56

Gene E. Bloch wrote:

> If you recall the formula for the area of a circle, it is A = 4 pi r-squared.

As I recall, the area of a circle is just pi * r-squared

> Thus a circle where r = 1, called a unit sphere,

How does a planer shape become a solid? It is a unit circle, not a unit
sphere.

> has an area of 4 pi,

No, it has an area of pi. Where did you find this factor of four?
Are you confused with the formula for the volume of a sphere
which is 4/3 * pi r-cubed

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