| Dionysius Lardner - Arithmetic - 1834 - 378 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... | |
| 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... | |
| 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 -^... | |
| Silas Totten - Algebra - 1836 - 360 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... | |
| 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,... | |
| 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,... | |
| 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,... | |
| Arithmetic - 1838 - 218 pages
...rule of three is derived.. In the following proportions the pupil will perceive that in every case the product of the means is equal to the product of the extremes. As 2 : 4 :: 6 : 12 2 : 8 :: 5 : 20 3 : 5 :: 6 : 10 7 : 11 :: 14 : 22 , Now suppose that we had the... | |
| Thomas H. Palmer - Education - 1840 - 300 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 intelligible... | |
| Thomas H. Palmer - Education - 1840 - 328 pages
...contains, or is contained, in the consequent of the second ; and, from this equality, it follows, that the product of the means is equal to the product of the extremes. For, if the numbers of the second ratio be double (treble, one half, or any other number of times)... | |
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