 | William Guy Peck - Algebra - 1875 - 348 pages
...fractions, we have, bc — ad; (2) hence, the following principles: 1°. If four quantities are in proportion, the product of the means is equal to the product of the extremes. Conversely, if we divide both members of (2) by cq, we have, - = - ; or, a : b : : c : d ; hence, ac... | |
 | Education Department,London - 1876 - 1010 pages
...angle : find the area. SECTION X. 1. Define ratio and proportion. Shew that when four numbers are in proportion, the product of the means is equal to the product of the extremes. 3. State as precisely as possible your view« as to the value of Mental Arithmetic simply asan Educational... | |
 | William Guy Peck - Conic sections - 1876 - 376 pages
...proportion is said to be transformed by division. PROPOSITION II. THEOREM. If four quantities are in proportion, the product of the means is equal to the product of the extremes. Assume the proportion, a : b :: c : d, whence - = - ; . . . (1) Multiplying both members of (1) by... | |
 | Samuel Mecutchen, George Mornton Sayre - Arithmetic - 1877 - 200 pages
...last terms of a proportion are called the Extremes, and the second and third terms the Means. In any proportion the product of the means is equal to the product of the extremes. Thus, in the proportion 4 : 8 :: 12 : 24, 8x 12 = 4 x 24. ORAL EXERCISES. 1. If 2 pounds of butter... | |
 | William Frothingham Bradbury - Algebra - 1877 - 280 pages
...fourth terms of a proportion are called the extremes, and the second and third the means. 106. In a proportion the product of the means is equal to the product of the extremes. Let a : b = с : d a с 6 = 5 Clearing of fractions, ad^bc A proportion is an equation ; and making... | |
 | George Albert Wentworth - Geometry - 1877 - 416 pages
...the diameter is a mem proportional between the segments of the diameter). Then tiCl = MCXCN, §259 (the product of the means is equal to the product of the extremes). QEF GEOMETRY. BOOK IV. PROPOSITION XXVI. PROBLEM. 359. To construct a parallelogram equivalent to a... | |
 | William Guy Peck - Arithmetic - 1877 - 428 pages
...have equal denominators ; hence, their numerators are equal, that is, 5 x 8 = 2 x 20 ; in this case the product of the means is equal to the product of the extremes. But we can reason in like manner on any proportion ; hence, we have the following principle : 1°.... | |
 | Stoddard A. Felter, Samuel Ashbel Farrand - Arithmetic - 1877 - 496 pages
...numerator by the other denominator, the products are equal. Hence, iu every proportion, PRINCIPLE I. — The product of the means is equal to the product of the extremes. If multiplying either the means or extremes together produces the same product, dividing this product... | |
 | George Albert Wentworth - Geometry - 1877 - 416 pages
...circumference to the diameter is a mean proportional between the segments of the diameter). aXb, §259 (flu product of the means is equal to the product of the extremes). QEF 355. COROLLARY 1. A square may be constructed eqxiivalent to a triangle, by taking for its side... | |
 | Edwin Pliny Seaver - Arithmetic - 1878 - 380 pages
...preceding illustration may be derived the following principles : 1. When four general numbers form a proportion, the product of the means is equal to the product of the extremes. 2. A missing extreme may be found by dividing the product of the means by the given extreme. 3. A missing... | |
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In any proportion, the product of the means is equal to the product of the extremes. 
