Books Books In any proportion, the product of the means is equal to the product of the extremes. Elements of Plane and Solid Geometry - Page 202
by George Albert Wentworth - 1877 - 398 pages ## The Art of Teaching School.

Josiah Rhinehart Sypher - History - 1872 - 336 pages
...second terms of a proportion must be the same as the relation between the third a^id fourth terms. The product of the means is equal to the product of the extremes. A missing extreme may be found by dividing the product of the means by the given extreme. A mean may... ## The Art of Teaching School: A Manual of Suggestions for the Use of Teachers ...

Josiah Rhinehart Sypher - Teaching - 1872 - 340 pages
...and second terms of a proportion must be the same as the relation between the third and fourth terms. The product of the means is equal to the product of the extremes. A missing extreme may be found by dividing the product of the means by the given extreme. A mean may... ## New Practical Arithmetic: In which the Science and Its Applications are ...

Henry Bartlett Maglathlin - Arithmetic - 1873 - 362 pages
...between the other two. Thus, In 12 : 6 :: 6 : 3, 6 is a mean proportional. 328. 1. In every proportion the product of -the means is equal to the product of the extremes. For, in the proportion 6 : 3 : : 4 : 2, since the ratios are equal (Art. 326), we have f = -J- Now,... ## Manual of Algebra

William Guy Peck - Algebra - 1875 - 348 pages
...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... ## Examination Christmas,1875

Education Department,London - 1876 - 1010 pages
...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... ## Manual of Geometry and Conic Sections: With Applications to Trigonometry and ...

William Guy Peck - Conic sections - 1876 - 394 pages
...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) ac Multiplying both members of (1) by... ## Complete Arithmetic: Comprising the New Intermediate Arithmetic and Part of ...

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... ## Bradbury's Elementary Algebra: Designed for the Use of High Schools and ...

William Frothingham Bradbury - Algebra - 1877 - 280 pages
...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... ## The New American Arithmetic, Part 3

Samuel Mecutchen, George Mornton Sayre - Arithmetic - 1877 - 200 pages
...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, 8X12 = 4X24. A Simple Proportion expresses the equality of two... 