 | Charles Austin Hobbs - Algebra - 1905 - 158 pages
...product of the extremes equals the product of the means. I. Solve the proportion 12 : 15 = x : 35. Making the product of the means equal to the product of the extremes, 15 x =420. a; =28. The numerical part of this example may be simplified by cancellation. 15x = 12 X35.... | |
 | Joseph Claudel - Mathematics - 1906 - 758 pages
...y, the above proportion may be written. or, noting that 3'jB or - = 6 — y b gives m = by' Putting the product of the means equal to the product of the extremes (729), Jij5. »<„_,,, or ah* — ay1 = ab* — Vx, and y1 = — x, • j which is the equation of... | |
 | John William Hopkins, Patrick Healy Underwood - Arithmetic - 1912 - 406 pages
...quantities given. These four quantities will then form a proportion which can be solved by placing the product of the means equal to the product of the extremes. It is well to state a problem so that one can see all around it ; eg 12 men do the work in 15 da. 9 men do... | |
 | Clara Avis Hart, Daniel D. Feldman - Geometry - 1912 - 504 pages
...algebra are usually simplified by this process, so, also, proportions may be simplified by placing the product of the means equal to the product of the extremes. 390. Cor. I. The mean proportional' between two numbers is equal to the square root of their product.... | |
 | Horace Wilmer Marsh, Annie Griswold Fordyce Marsh - Mathematics - 1912 - 494 pages
...4^=^Az S22 But si=what? Therefore si2=what? Substitute this value of si2 in the proportion and take the product of the means equal to the product of the extremes. Write the following law: The area of any regular polygon equals the square of one of its sides multiplied... | |
 | Claude Irwin Palmer, Daniel Pomeroy Taylor - Geometry, Plane - 1915 - 336 pages
...hypotenuse equals the sum of the squares of the two sides. Proof. In each proportion of § 435, take the product of the means equal to the product of the extremes. Then o? = a'c and 62 = b'c. Adding, a2 + b2 = (a'+b') c. But a'-\-b' = c. 439. Theorem. A perpendicular... | |
 | George Johnson - Arithmetic - 1916 - 64 pages
...as the greatest is to the third from it so is the second, next to it, to the fourth, for this makes the product of the means equal to the product of the extremes ; now again if the difference between the greatest and the term next to it can be shown to be equal... | |
 | Claude Irwin Palmer, Daniel Pomeroy Taylor - Geometry - 1918 - 460 pages
...hypotenuse equals the sum of the squares of the two sides. Proof. In each proportion of § 435, take the product of the means equal to the product of the extremes. Then a2 = a'c and b- = b'c. Adding, a2+62=(a'+6')c. But a'+b' = c. 439. Theorem. A perpendicular drawn... | |
 | United States - 1918 - 840 pages
...by 4 feet by 20 feet. This is reduced to the simple proportion, 144 x : 3456 : : 3600 : 4800. Making the product of the means equal to the product of the extremes, the value of x is found to be 18. Answer, 18 men. SQUARE AND CUBE ROOT. X The square of a number is... | |
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If four quantities are proportional, THE ORDER OF THE MEANS, OR OF THE EXTREMES, OR OF THE TERMS OF BOTH COUPLETS, MAY BE INVERTED, WITHOUT DESTROYING THE PROPORTION. 
