Sect. I.

Problem. X.

To find the Cube-Root of any Number under 1000.000.000.

Place the Lines D and E, so as 10 at the end of D, be even with 10 at the end of E, then against any Number upon E, you have the Cube-Root thereof upon D. Et Contr.

    Note, 1. When the Number given consists of 1, 4, or 7 places of integers, find it in the first Radius of the Line E, and against it you have the Cube-Root sought. Example: let the Number given be 3375: I seek this in the first Radius in the Line E, and against it I find 15 upon D, which is the Cube-Root of 3375, and so is 212 the Cube-Root of 9528128.

    2. When the Number given consists of 2, 5, or 8 places of Integers, find it in the second Radius upon E, and against it is the Root sought. Example: Suppose 35.937 were propoounded, find this in the second Radius upon E, and against it is 3.3, the Cube-Root upon D; in like manner is 275 the Cube-Root of 20796875.

    3. When the Number given consists of 3, 6, or 9 places of Integers, seek it in the third Radius, &c. and against it is the Cube-Root: Thus against 125 in the third Radius upon E, I find 5 the Cube-Root, and so likewise is 888 the Cube-Root of 700.227.072.

    Lastly, to know how many places of Integers must be in the Cube-Root of any Number given.

    Put a Point over the place of Units in the Number given, then omitting 2, point every third Figure toward the left hand, then tell how many Points, for so many places of Integers must the Cube-Root consist of.

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This page was last updated on 29 March 2000.