Cross sectional area (NOT A QUESTION)

moonman239

Just for those who don't know a thing about cross sectional areas, I thought I'd explain.

A cross sectional area describes the area of a flat (2-dimensional) representation of a 3-dimensional object. So if I cut a cylinder, instead of seeing two circles, I see four circles (unless there are other circles in my environment). The cross-sectional area is the area of either of the two circles.

For a cylinder or right solid, the cross-sectional area is the area of the base.
For a sphere, the cross sectional area is the area of a circle with the same radius (pi*r²).
For an ellipsoid, the cross sectional area is the area of an ellipse with the same long (a) and short (b) axes (pi*ab).

Landau

I don't know what to say. Thanks for sharing?

theoryiscool

lol at landau's response

moonman239

Oh, for an oblate ellipsoid (such as Earth), where lines of latitude are circular, the area is simply pi*(r^2)