Books Books In any proportion, the product of the means is equal to the product of the extremes. Elements of Plane Geometry: For the Use of Schools - Page 53
by Nicholas Tillinghast - 1844 - 96 pages ## Treatise on Arithmetic, Practical and Theoretical

Dionysius Lardner - Arithmetic - 1834 - 353 pages
...found. (379-) Since four numbers, which are in proportion, will continue to be in proportion so long as the product of the means is equal to the product of the extremes, it follows that we may make any of the following changes in the order of the four terms, without destroying... ## Encyclopædia Americana: A Popular Dictionary of Arts, Sciences ..., Volume 10

Francis Lieber, Edward Wigglesworth - Encyclopedias and dictionaries - 1835 - 618 pages
...proportion, the sum of the extremes is equal to that of the means, and, in geometrical proportions, the product of the means is equal to the product of the extremes, either extreme (or mean) may be found in the former, by subtracting the given extreme (or mean) from... ## A New Introduction to the Science of Algebra ...

Silas Totten - Algebra - 1836 - 320 pages
...progression 2, 5, 8, 11, &c. to 31 terms. Ans. 1457. GEOMETRICAL PROPORTIONS. (65.) In every geometrical proportion, the product of the means is equal to the product of the extremes. Take the proportion 12 : 4 = 18 : 6, or -T- = -»-. Now, if 12 18 we reduce the fractions -j- and -^... ## A New Introduction to the Science of Algebra...

Silas Totten - Algebra - 1836 - 362 pages
...— . Putting x in the place of the unknown term, the proportion becomes 12 : 4 = 18 : x ; and since the product of the means is equal to the product of the extremes (05), we have 12 xx = 18 x 4, or 12 x - 72 ; and as 1£ times x = 72, it ja 72 evident that x, the... ## A Treatise on the Elements of Algebra

James Bryce - Algebra - 1837 - 322 pages
...72— 4я+8; whence we easily find 4. Given, — £— : — ^ — : : 7 : 4, to find ». Since, in a proportion, the product of the means is equal to the product of the extremes (Eue. VI. 16), it follows that 126—7х 10х+8= - 4 - O2 By multiplication, 40 x +32 =126— 7x. whence,... ## A Practical and Theoretical System of Arithmetic: Containing a New System of ...

George Willson - Arithmetic - 1838 - 194 pages
...geometrical proportion consisting of four terms, have been explained on page 92, and the reason assigned why the product of the means is equal to the product of the extremes. This equality between their products suggests an obvious method of finding any term of a proportion,... ## A Practical and Theoretical System of Arithmetic: Containing Several New ...

George Willson - Arithmetic - 1838 - 194 pages
...geometrical proportion consisting of four terms, have been explained on page 92, and the reason assigned why the product of the means is equal to the product of the extremes. This equality between their products suggests an obvious method of rinding any term of a proportion,... ## The Western Practical Arithmetic: Wherein the Rules are Illustrated, and ...

Arithmetic - 1838 - 204 pages
...there is no ratio between 2 inches and 6 hogs. In every case of proportion the pupil will observe that the product of the means is equal to the product of the extremes, and it is from this fundamental law that the rule for the solution in the single rule of three is derived..... ## The Teacher's Manual: Being an Exposition of an Efficient and Economical ...

Thomas H. Palmer - Education - 1840 - 330 pages
...whatever. Now, as these equal products are those of the extremes and means, we thus have the rule of proportion : The product of the means is equal to the product of the extremes. [Let this be demonstrated, a few times, on the blackboard, till it has become familiar. It will be... 