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CHAPTER VII-
BASUREMENT OF ABRAS.
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The rule for arriving at the minutely accurate value of the figure formed in the interspace caused by three (oqual) oiroular figures touching each other :
84). The minutely accurate measure of the area of an equilateral triangle, each side of which is oqual in measure to the diameter (of the ciroles) is diminished by half the area of any of the three equal) ciroles. The remainder happens to be the measure of the interspace are caused by three (mutually touching equal oiroles).
An example in illustration thereof. 851. What is the minutely accurate oalculated value of a figure forming the interspace enclosed by three mutually touching (equal) ciroles the diameter (of each) of wbich is 4 in measure P
The rule for arriving at the minutely accurate values of the diagonal, the perpendicular and the area in the case of a (regular) six-sided figure :
864. In the case of a (regular) six-sided figure, the measuro of the side, the square of the side, the square of the square of the , side multiplied respectively by 2, 3 and 3 give riso, in that same
order, to the values of the diagonal, of the squaro of the perpendi. cular, and of the square of the measure of the area.
84). Bimilarly the figure here eluci. dates at once the reason of the rule :
861. The role seems to contemplato a regular hexagon. Tho formula given for the value of the area of the hexagon is 3a, where a is the length of sida
The oorrect formula, however, is
