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Four quantities are in proportion when the ratio of the first to the second is equal to the ratio of the third to the fourth.
Elements of Geometry Upon the Inductive Method: To which is Added an ... - Page 24
by James Hayward - 1829 - 172 pages

## The Texas Mathematics Teachers' Bulletin, Volumes 1-7

Mathematics - 1915 - 832 pages
...ratios is said to form a proportion, or in other words four quantities are said to be in proportion when the ratio of the first to the second is equal to the ratio of the third to the fourth. Thus 5 ft. \$25 2 ft. \$10 is a proportion. This is often written 5 ft. : 2 ft. :: \$25 : \$10...

## Secondary Mathematics: I-, Volume 1

Harry Morton Keal, Nancy Seymour Phelps - Mathematics - 1917 - 240 pages
...x+5 x+25 x-4 x-2 5x-7 l0x+11 12. 3x-5 6x+ 7 3x DIRECT VARIATION 91 20. Find three consecutive numbers such that the ratio of the first to the second is equal to the ratio of 5 times the third to 5 times the first plus 16. Variation 101 Direct Proportion: If a train travels...

Harry Morton Keal - Mathematics - 1917 - 148 pages
...ratio of 21° to the supplement of the same angle. Find the angle. 20. Find three consecutive numbers such that the ratio of the first to the second is equal to the ratio of 5 times the third to 5 times the first plus 16. Variation 101 Direct Proportion: If a train travels...

## Elementary Algebra

George Hervey Hallett, Robert Franklin Anderson - Algebra - 1917 - 432 pages
...а с 174. Continued proportion. Three or more numbers are said to be in continued proportion when the ratio of the first to the second is equal to the ratio of the second to the third, and so on. Thus, a, 6, c, d are in continued proportion if, 175. Mean proportional....

## Elements of Algebra

Henry Sinclair Hall - 1918 - 382 pages
...y, or г = ж + y. У PROPORTION. 348. DEFINITION. Four quantities are said to be in proportion when the ratio of the first to the second is equal to the ratio of the third to the fourth. The four quantities are called proportionals, or the terms of the proportion. Thus, if - =...

## Appleton's New Practical Cyclopedia: A New Work of Reference Based ..., Volume 5

...by division, which one quantity bears to another. Four quantities are said to be in proportion when the ratio of the first to the second is equal to the ratio of the third to the fourth. A proportion may be written in either of two ways; thus if the ratio of a to & is equal to...