 | 1897 - 366 pages
...Arithmetic. In our grandfathers' Arithmetics, it was called " The rule of three." 320. Rule I. — In any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 321.... | |
 | International Correspondence Schools - Electrical engineering - 1897 - 346 pages
...arithmetic. In our grandfathers' arithmetics, it was called "The rule of three." 310. Rule 4O. — In any proportion, the product of the extremes equals the product of thc means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal... | |
 | International Correspondence Schools - Surveying - 1898 - 518 pages
...Arithmetic. In our grandfathers' Arithmetics, it was called " The rule of three." 320. Rule I.—ln any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 321.... | |
 | Arthur A. Dodd, B. Thomas Chace - Geometry - 1898 - 468 pages
...of Prop. I. is given below to serve as an example of proofs in Proportion. I. If four numbers are in proportion, the product of the extremes equals the product of the means. Given: a : b = c : d. To prove: ad=bc. Proof: a - = c - d , [Hyp.] .'. ad = be. [Ax. If the same operation... | |
 | International Correspondence Schools - Civil engineering - 1899 - 722 pages
...Arithmetic. In our grandfathers' Arithmetics, it was called " The rule of three." 3 2O. Rule I. — In any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 321.... | |
 | Analytical chemistry - 1900 - 532 pages
...of arithmetic. In our grandfathers' arithmetics, it was called "The rule of three." 139. Rule I. — In any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17:51 = 14:42. 17 X 42 = 51 X 14, since both products equal 714. MO. Rule... | |
 | 1900 - 728 pages
...Arithmetic. In our grandfathers' Arithmetics, it was called " The rule of three." 320. Rule I. — In any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 321.... | |
 | International Correspondence Schools - Marine engineering - 1900 - 614 pages
...arithmetic. In our grandfathers' arithmetics, it was called " The rule of three." 310. Rule 4O. — In any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 311.... | |
 | International Correspondence Schools - Coal mines and mining - 1900 - 732 pages
...Arithmetic. In our grandfathers' Arithmetics, it was called " The rule of three." 320. Rule I. — In any proportion, ' the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 321.... | |
 | International Correspondence Schools - Electric lighting - 1901 - 630 pages
...sections of arithmetic. In our grandfathers' arithmetics, it was called "The rule of three." 55. Rule. — In any proportion, the product of the extremes equals the product of the means. Thus, in the proportion, 17 : 51 = 14 : 42. 17 X 42 = 51 X 14, since both products equal 714. 56. Rule.... | |
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In any proportion, the product of the extremes equals the product of the means. 
