1. Identify the axis of symmetry. For many applications, this will be the longest axis or the longitudinal axis. 2. Identify the shape projected onto a plane that passes through the
http://www.ehow.com/how_4913182_calculatecross_se...

If I am correctly understanding the question. You are simply looking for the area of a circle or pi * R^2 or pi/4 * D^2.  The formula above is correct for the planar cross section
http://wiki.answers.com/Q/How_do_you_calculate_the...

First measure across a circle to find its diameter. Half of the diameter is equal to the radius. The area of a circle is equal to 1/2 x pi (˜ 3.14) x radius squared.
http://www.ask.com/webanswers/Science/Mathematics...

You could integrate the resistance of thinslices of the object: This is essentially a combination of the fact that series resistances add and the formula for the resistance of an
http://www.quora.com/ElectricalEngineering/Howdo...
