. Haswell's engineers' and mechanics' pocket-book ... Tofmd the Area of an Irregular Polygon, abcdefg—fig. —Draw diagonals to divide the ligure into trapeziums andtriangles ; find the area of each separately, and the sum of the wholewill give the area required. To find the Area of a Long Irregular Figure, bdca—fig. —Take the breadth in several places, and at equal distan-ces apart; add them together, and divide the sum by the numberof breadths for the mean breadth ; then multiply that by the lengthof the figure, and the product will be the area. OF 14. 6 A/ rr^ 1 ^^ ?
. Haswell's engineers' and mechanics' pocket-book ... Tofmd the Area of an Irregular Polygon, abcdefg—fig. —Draw diagonals to divide the ligure into trapeziums andtriangles ; find the area of each separately, and the sum of the wholewill give the area required. To find the Area of a Long Irregular Figure, bdca—fig. —Take the breadth in several places, and at equal distan-ces apart; add them together, and divide the sum by the numberof breadths for the mean breadth ; then multiply that by the lengthof the figure, and the product will be the area. OF 14. 6 A/ rr^ 1 ^^ ?^^ / o \ \^ q\ ^\ hi. To find the Diameter and Circumference of any 1.—Multiply the diameter by , and the product willbe the circumference. F 62 MENSURATION OF SURFACES. Rule 2.—Divide the circumference by , and the quotientwill be the diameter. Rule 3.—Or, as 7 is to 22, so is the diameter to the circumfer-ence. Or, as 22 is to 7, so is the circumference to the diameter. Or, as 113 is to 355, so is the diameter to the circumference, &c To find the Area of a Circle. Rule 1.—Multiply the square of the diameter by .7854, or thesquare of the circumference by .07958, and the product will be thearea. Rule 2.—Multiply half the circumference by half the diameter. Rule 3.—As 14 is to 11, %o is the square of the diameter to thearea , or, as 88 is to 7, so is the square of the circumference to thearea. To find the Length of any Arc of a Circle—fig. 12. Rule 1.—From 8 times the chord of half the arc , subtract thechord ab of the
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Keywords: ., bookcentury1800, bookdecade184, booksubjectmechanicalengineering
