 | International Correspondence Schools - Arithmetic - 1904 - 656 pages
...arithmetic. In our grandfathers' arithmetics, it was called "The rule of three." 69. 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. 70. Rule.... | |
 | Charles Austin Hobbs - Algebra - 1905 - 158 pages
...that a proportion is merely a fractional equation. Clearing of fractions, ad = be. That is, in any proportion the product of the extremes equals the product of the means. I. Solve the proportion 12 : 15 = x : 35. Making the product of the means equal to the product of the... | |
 | John Charles Stone, James Franklin Millis - Algebra - 1905 - 776 pages
...most important principles in proportion. The student should master these principles. 195. In any true proportion the product of the extremes equals the product of the means. Suppose a : b=c : d. Written in fractional form, т= jMultiplying by bd, ad=bc) wh ich -pro ves the... | |
 | Education - 1914 - 220 pages
...and 15 in the above) are called the extremes and the second and third (10 and 24) the means. In every proportion the product of the extremes equals the product of the means. One quantity varies as another when an increase or decrease in one causes a corresponding increase... | |
 | International Correspondence Schools - Arithmetic - 1906 - 576 pages
...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. 17x42 = 51x14, since both products equal 714. 140. Kule II.... | |
 | Joseph Victor Collins - Algebra - 1908 - 442 pages
...between the first and last terms. 207. Fundamental Theorems about a Proportion. 1. If four quantities are in proportion, the product of the extremes equals the product of the means. If - = -, then ad = 6c (by Mult. Ax.). bd SUGGESTION. Both sides of the given equation are multiplied... | |
 | Joseph Gregory Horner - Engineering - 1908 - 556 pages
...to 9." The first and last quantities are the extremes, and the second and third, the means. In any proportion the product of the extremes equals the product of the means, as will be seen in the above example. Therefore if three terms are given the fourth may be found. See... | |
 | Charles E. Larard, Henry A. Golding - Engineering - 1909 - 556 pages
...80 90 *00 & 9 . I0 Proportion, Ratios, Percentages. — We have already stated (p. 13) that in any proportion the product of the extremes equals the product of the means, so that the fourth term in proportion equals the product of the second and third terms divided by the... | |
 | George Wentworth, David Eugene Smith - Arithmetic - 1909 - 290 pages
...proportion the product of the extremes equals the product of the means. 66. Finding a Missing Term in a Proportion. The product of the extremes equals the product of the means (§ 6o). Therefore, either extreme equals the, product of the means divided by the other extreme ;... | |
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In any proportion, the product of the extremes equals the product of the means. 
