 | Adrien Marie Legendre - Geometry - 1836 - 394 pages
...the first has the same ratio to the second, that the second ha-s to the third ; and then the middle term is said to be a mean proportional between the other two. 5. Magnitudes arc said to be in proportion by inversion, or inversely, when the consequents are taken... | |
 | Algebra - 1838 - 372 pages
...when the first has the same ratio to the second that the second has to the third ; and then the middle term is said to be a mean proportional between the other two. 172. Quantities are said to be in proportion fay inversion, or inversely, when the consequents are... | |
 | Charles Davies - Algebra - 1839 - 264 pages
...when the first has the same ratio to the second that the second has to the third ; and then the middle term is said to be a mean proportional between the other two. For example, 3 : 6 : : 6 : 12; and 6 is a mean proportional between 3 and 12. 148. Quantities are said... | |
 | Charles Davies - Algebra - 1842 - 284 pages
...when the first has the same ratio to the second that the second has to the third ; and then the middle term is said to be a mean proportional between the other two. For example, 3 : 6 : : 6 : 12; and 6 is a mean proportional between 3 and 12. 148. Quantities are said... | |
 | Charles Davies - Algebra - 1842 - 368 pages
...when the first has the same ratio to the second that the second has to the third ; and then the middle term is said to be a mean proportional between the other two. 172. Quantities are said to be in proportion by inversion, or t'nversely, when the consequents are... | |
 | William Watson (of Beverley.) - 1844 - 200 pages
...proportion - = - whence xz = j/2 y ar THEOREM 2 When four numbers or quantities are in geometrical proportion, the product of the extremes is equal to the product of the means・ Thus a, b, c, d, are in geometrical ac proportion, when* - = -, or ad ・=， b c・ That is, as a 1 b 11... | |
 | James Bates Thomson - Algebra - 1844 - 272 pages
...SECTION XIV. GEOMETRICAL PROPORTION AND PROGRESSION. ART. 337. If four quantities are in geometrical proportion, the product of the extremes is equal to the product of the means. Thus, 12 : 8 :: 15 : 10 ; therefore 12x10 = 8x15. Hence, 338. Any factor may be transferred from one of the... | |
 | Charles Davies - Algebra - 1845 - 382 pages
...when the first has the same ratio to the second that the second has to the third ; and then the middle term is said to be a mean proportional between the other two. 172. Quantities are said to be in proportion by inversion, or inversely, when the consequents are made... | |
 | James Bates Thomson - Arithmetic - 1846 - 354 pages
...same ratio to the second, as the fourth has to the third. Thus 8 6 T— 5324. If four numbers are in proportion, the product of the extremes is equal to the product of the means. Thus 8 : 4 : : 6 : 3 is a proportion : for |— |. (Art. 318.) Now 8x3=4x6. Again, 12 : 6 : : £ : \ is... | |
 | James Bates Thomson - Arithmetic - 1846 - 402 pages
...ratio to the second, as the fourth has to the third. Thus 4 — £ 4 — 3' ;. If four numbers are in proportion, the product of the extremes is equal to the product of the means. Thus 8 : 4 : : 6 : 3 is a proportion : for f = f . (Art. 318.) Now 8x3 = 4x6. Again, 12 : 6 : : £ : J is... | |
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In every proportion the product of the extremes is equal to the product of the means. Thus, in the proportion 3 : 5 : : 6 : 10 we have 3 x 10 = 5 x 6. 
