Twentieth century hand-book for steam engineers and electricians, with questions and answers .. (1905)
Swingle, C. F. [from old catalog], Horstmann, Henry Charles, 1858- [from old catalog], Tousley, Victor Hugo, 1875- [from old catalog] · Chicago, F. J. Drake & co. · leaf 444
s circle is 2 in., instead of 1, you can readily see byFig. 13 that its area is four times as great or 2 x 2 = 4.We then multiply by the standard number .7854 inorder to find the area contained in the two-inch circle;and if the diameter were 3 in., then 3x3 = 9, and9 x .7854 would be the area in… … FIGURE 12. 26 ELECTRICITY FOR ENGINEERS quarter-circle from one adjacent corner to the otheradjacent corner, the area inscribed by the compasswould again be .7854 of a square inch. The above will explain to the reader the relation
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