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# NETA II test question (cable area)

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## NETA II test question (cable area)

A wire that has a diameter of 162 mils has an area of _____ circular mils.
Your Answer: 20,162
Help: A = d2

Last I checked. A=pi*R^2

thus,

162/2=81=R,
81^2=6561,
6561*3.14= 20601.54

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Originally Posted by dbryce89
A wire that has a diameter of 162 mils has an area of _____ circular mils.
Your Answer: 20,162
Help: A = d2

Last I checked. A=pi*R^2

thus,

162/2=81=R,
81^2=6561,
6561*3.14= 20601.54
Upon further research there is a specific unit associated with this question, "circular mils." I guess using Pi is just too difficult.....

Here is what wiki had to say.

A circular mil is a unit of area, equal to the area of a circle with a diameter of one mil (one thousandth of an inch). It corresponds to 5.067×10−4 mm². It is a unit intended for referring to the area of a wire with a circular cross section. As the area in circular mils can be calculated without reference to π, the unit makes conversion between cross section and diameter of a wire considerably easier.

The area in circular mils, A, of a circle with a diameter of d mils, is given by the formula:

A=d^{2}