Key to the American Common-school Arithmetic

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Tappan, Whittemore & Mason, 1849
 

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Page 96 - From half the sum of the three sides subtract each side severally; multiply together the half sum and the three remainders, and extract the square root of the product. The area of an equilateral triangle is equal to one fourth the square of one of its sides multiplied by the square root of 3, = - — ;, a being the side; or 4 a* X .433013. Hypothenuse and one side of right-angled triangle given, to flnd other side. Required side = t'hyp
Page 114 - The Contents of similar solids are to each other as the cubes of their like dimensions. Conversely, The Like Dimensions of similar solids are as the cube roots of their contents.
Page 9 - Any number may be divided by an aliquot part of a hundred when its two right-hand figures may be thus divided. Any number may be divided by an aliquot part of a thousand when its three right-hand figures may be thus divided. Any number divided by 3 or 9 will leave the same remainder as the sum of its digits divided by 3 or 9.
Page 99 - Tlie like dimensions of similar solids are to each other as the cube roots of their volumes.
Page 4 - In the same manner perform the following : — 2. 4893 — 1231? . 5. 4807 — 1614? 3. 5987 — 3125? 6. 9318 — 2106 ? 4. 8958 — 6713 ? 7. 6985 — 1401 ? C. If a figure of the subtrahend is larger than the corresponding figure of the minuend, we take one of the next higher denomination of the minuend, and reduce ({. e., change) it to the required denomination, as in the following example : — 1.
Page 98 - It is required to find the length of the edge of this cube. Since the volume of a cube is equal to the cube of one of its edges, an edge may be found by extracting the cube root of the volume. Since 405224 consists of two periods, its cube root will consist of two figures.
Page 102 - An equilibrium is produced in all the levers, when the weight multiplied by its distance from the fulcrum is equal to the product of the power multiplied by its distance from the fulcrum. That is, The weight is to the power, as the distance from the power to the fulcrum, is to the distance from the weight to the fulcrum.
Page 2 - ... from the bottom to the top, and then from the top to the bottom, while the pupil gays aloud, one, two, three, four, five, &c.
Page 92 - From i it follows that the diameters and the radii of circles are to each other as the square roots of their areas.
Page 107 - ... that its cross or horizontal diameter is a lever of the second order, the fulcrum being the point of contact with the fixed part of the rope, the power is the movable part of the rope, and the weight rests on the pivot at the centre. Such a wheel would afford a mechanical advantage as 2 to 1, since the power is twice as far from the fulcrum as the weight is, and the power of a number of them would be equal to twice their number ; the corresponding fixed pulleys in the upper block having no mechanical...

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