Page:The Rhind Mathematical Papyrus, Volume I.pdf/104

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88
CHAPTER II—GEOMETRY
[43
  1 10
\ 10 106
\ 12\3 719
Total 113
  1 113
  2 22712118
  \ 4 45519
  1 45519
  110 4512190
\ 120 2212141180

This solution for a long time baffled the ingenuity of Egyptologists, but the correct interpretation was finally discovered by Schack-Schackenburg (1899, see Peet, page 83).

In the first place, the papyrus states that the height of the granary is 9 and the breadth (diameter) 6, and in the solution, when we find 4 as 23 of 6, the author again calls 6 the breadth; but the solution is for a cylinder in which 9 is the diameter and 6 the height.[1]

Then the method of solution is not that used in 41 and 42, but a second one (employed for a similar problem in the Kahun papyrus, Griffith, 1897), giving the volume directly in khar and not first in cubed cubits. It may be expressed in the following rule: Add to the diameter its 13; square, and multiply by 23 of the height. In Problem 43 the addition of its 13 to the diameter makes 12, the square is 144, and 23 of the height is 4. With these numbers the rule gives 576 khar,and this is just what the author would have obtained if he had followed the solutions of 41 and 42.[2]

But the author, before taking the steps of this rule, deducts from the diameter its 19, as by the other rule, and so obtains a result which is (89)2 of the correct result, namely, 45519 khan[3]

  1. There is some confusion in Peet’s explanation of this mistake (page 84). He supposes that the statement was correct in the original papyrus, but that "a later scribe, seeing in the first line of working the subtraction of a ninth of 9 from 9, . . . concluded that 9 must be the diameter and not the height, and so he transposed the two dimensions in the statement," but if the statement now in the papyrus is the result of such a transposition the transposition must have been the other way.
  2. In modern form the number of khar according to the two methods is expressed by the formulae (89d)2 h.23 and (13d)2.23h. both of which reduce to 3127hd2
  3. Eisenlohr translated the word now read khar as "bodily content" and supposed that the addition of 12 to reduce cubed cubits to khar was a part of the calculation of the cubed cubits. This is the same as multiplying the base by 12 of the height instead of by the height itself, and to explain this he supposes that the given base in 41 and 42 is the upper base, and that the lower base is larger. When he comes to Problem 43 he has great difficulty. In the first place, he finds that 89 of the diameter of the base is multiplied by 13(13 of it added) before squaring, as if the base were an ellipse with one axis 169 of the other, or as if our author intended to get the lower base or some section between the two. Then the area obtained is multiplied by 23 of the height instead of 32, which might be because he had taken