Page:The Rhind Mathematical Papyrus, Volume I.pdf/102

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CHAPTER II. GEOMETRY

SECTION I

Problems 41-46. Problems of Volume

Problem 41
Find the volume of a cylindrical granary of diameter 9 and height 10.

Take away 19 of 9, namely, 1; the remainder is 8. Multiply 8 times 8; it makes 64. Multiply 64 times 10; it makes 640 cubed cubits. Add 12 of it to it; it makes 960, its contents in khar. Take 120 of 960, namely 48. 4800 hekat of grain will go into it.

Method of working out:

  1 8   2 16   4 32 \ 8 64.   1 64 \ 10 640 \ 12 320
Total 960
  110 96
\ 20 48.

As explained in the Introduction (pages 35-36), the author, in order to obtain the volume of the cylinder, subtracts from the diameter its 19, squares the remainder, and multiplies by the altitude. In this way he finds that 640 is the contents of the granary in cubed cubits. As a khar is 23 of a cubed cubit he adds to 640 its 12, which gives him 960 as the number of khar in the granary. Finally, dividing by 20, he obtains 48 as the number of hundreds of quadruple hekat. (See Introduction, page 32.)

Problem 42
Find the volume of a cylindrical granary of diameter 10 and height 10.

Take away 19 of 10, namely 119;the remainder is 82316118. Multiply 82316118 times 82316118; it makes 7911081324. Multiply 7911081324