| James Bates Thomson - Arithmetic - 1847 - 424 pages
...324 SIMPLE [SECT. XIV. fieiiviisfrat-tfin. — If four numbers are proportional, we Lave seen th:\t **the product of the means is equal to the product of the** i-xtrimcs ; (Art. 4!)S:) therefore the pr id let of tile acca ul and t.hv'd terms must be equal to... | |
| Joseph Ray - Algebra - 1848 - 250 pages
...x= one part; then 55— £= the other. By the question, x : 55 — x : : 2 : 3. Then, since, m every **proportion, the product of the means is equal to the product of the extremes,** we have 3x=2(55 — x)=110 — 2x 5x=110 x=22, and 55— x=33, as before. Or thus : Let x= one part,... | |
| James Bates Thomson - Arithmetic - 1848 - 432 pages
...is simple proportion proved ? Demonstration.—If four numbers are proportional, we have seen that **the product of the means is equal to the product of the extremes;** (Art. 498;) therefore the product of the second and third terms must be equal to that of the first... | |
| Pliny Earle Chase - Arithmetic - 1848 - 240 pages
...consequents may, therefore, change places in a variety of ways, the proportion always continuing so long as **the product of the means is equal to the product of the extremes.** Then, whenever one of the extremes and the two means are given, to find the other extreme, Divide the... | |
| Almon Ticknor - Arithmetic - 1848 - 122 pages
...means, and the first and fourth terms the extremes : 2 : (4 : : 8) : 16 _4X _2X 32 32 Here we see that **the product of the means is equal to the product of the extremes.** If 2 pounds of tea cost 4 dollars, •what will 8 pounds cost 1 6. Here the price of the tea is 2 dollars... | |
| Zadock Thompson - Arithmetic - 1848 - 184 pages
...product rr the first and fourth equals the product of the second and third, or, m other words, that tlie **product of the means is equal to the product of the extremes.** 194. In the proportion, 4 : 6 : : 12 : 18, the order of the terms may be altered without destroying... | |
| Joseph Ray - Algebra - 1848 - 248 pages
...we have the following proportions : z+5 : y+5 : : 5 : 6 a:— 5 : y— 5 : : 3 : 4. Since, in every **proportion, the product of the means is equal to the product of the extremes,** we have the two equations 6(x+5)=5(y+5) 4(x-5)=3(y-5) From these equations, the values of z and y are... | |
| Joseph Ray - Algebra - 1852 - 410 pages
...5x for the second, which fulfills the first condition. Then, Sx-\-Q : 5*+9 : : 6 : 7. But in every **proportion, the product of the means is equal to the product of the extremes.** (Arith. Part 3rd, Art. 209.) Hence, 6(5o:+9)=7(3;c+9). 30*4-54=2 la-l-63, 30*— 21*=63— 34, .-.... | |
| John Fair Stoddard - Arithmetic - 1852 - 324 pages
...obtained by dividing the third term by the fourth, we can readily deduce the following PROPOSITIONS. , 1. **The product of the means is equal to the product of the extremes.** Therefore. 2. If the product of the means be divided by one extreme, the quotient will be the other... | |
| Sarah Porter - 1852 - 286 pages
...multiplied by the third term : ji 1 fi for as 7 : 8 : : 14 : 16, therefore - = — = 8x14=16x7, or **the product of the means is equal to the product of the extremes.** Hence if any three numbers be given, a fourth proportional to them may be found, such as, this 4th... | |
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