 | Charles Austin Hobbs - Arithmetic - 1889 - 370 pages
...proportional between 2 and 18. The solution of problems in proportion depends on the following principle : — In any proportion the product of the extremes equals the product of the means. This can be proved in any proportion by expressing the ratios in fractional form, and then multiplying... | |
 | Charles Austin Hobbs - Arithmetic - 1889 - 366 pages
...proportional between 2 and 18. The solution of problems in proportion depends on the following principle : — In any proportion the product of the extremes equals the product of the menus. This can be proved in any proportion by expressing the ratios in fractional form, and then multiplying... | |
 | James Wallace MacDonald - Geometry - 1889 - 80 pages
...What are equimultiples of two quantities? Proposition I. A Theorem. 117. If four quantities are in proportion, the product of the extremes equals the product of the means. COROLLARY. A mean proportional is equal to the square root of the product of the other two terms. Proposition... | |
 | James Wallace MacDonald - Geometry - 1894 - 76 pages
...What are equimultiples of two quantities? Proposition I. A Theorem. 117. If four quantities are in proportion, the product of the extremes equals the product of the means. COROLLARY. A mean proportional is equal to the square root of the product of the other two terms. Proposition... | |
 | David Martin Sensenig - Algebra - 1890 - 556 pages
...to the third, or as the reciprocal of the third is to the reciprocal of the fourth. Theorems. 430. In any proportion the product of the extremes equals the product of the means. Given a : b : : с : d. Prove a X d — Ъ X с. Demonstration : -j- = -3- [418]. Clearing of fractions,... | |
 | Isaac Hammond Morris - Geometry, Plane - 1890 - 440 pages
...to the left. MULTIPLICATION It has already been shown in Chapter IV., that when four munbers are in proportion, the product of the extremes equals the product of the means. If one of the extremes be unity, then the product of the means equals the other extreme. If we take... | |
 | Andrew Wheeler Phillips, Irving Fisher - Geometry - 1896 - 276 pages
...corresponding arcs, AB and A'B'. TRANSFORMATION OF PROPORTIONS 250. THEOREM. If four numbers are in proportion, the product of the extremes equals the product of the means. GIVEN £ = £. (1) bd To PROVE ad=bc. (2) Clear (1) of fractions, ie, multiply both sides by bd, the... | |
 | Emerson Elbridge White - Algebra - 1896 - 418 pages
...equation - = - ; and, by simple transformations of this PROPOS тоне. 522. If four numbers are in proportion, the product of the extremes equals the product of the means. Let a : b = c: d; a с then - = — bd Multiplying by bd, ad = be. 523. It follows from the above,... | |
 | Andrew Wheeler Phillips, Irving Fisher - Geometry, Modern - 1896 - 276 pages
...corresponding arcs, AB and A'B'. TRANSFORMATION OF PROPORTIONS 230. THEOREM. If four numbers are in proportion, the product of the extremes equals the product of the means. GIVEN £ = f. (i) bd To PROVE ad=bc. (2) Clear (i) of fractions, ie, multiply both sides by bdt the... | |
 | International Correspondence Schools - Electrical engineering - 1897 - 672 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. Rule... | |
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In any proportion, the product of the extremes equals the product of the means. 
