To Find The Solidity Of A Cone Or A Pyramid

Rule. - Multiply the area of the Base by the Perpendicular height, and 1/3 the product will be the Solidity.

Example. - The base of a cone, fig. 13, is 2 1/4 ft., and the height is 3 3/4 feet, what is the Solidity.

2.25 X .7851 x 3.75

-----------------------------= 497 cubic feet the Solidity.

Fig. 13.

To Find The Solidity Of The Frustrum Of A Cone

Rule. - To the Product of the diameters ef the ends, add 1/3 the square of the difference of the diameters; multiply the sum by .7854 and the product will be the mean area between the ends, which multiplied by the perpendicular's height of the Frustrom, gives the Solidity.

Example. - The diameter of the large end of a Frustrom of a Cone, fig. i4, is 10 feet, that of the smaller end is 6 feet, and the perpendicular height 12 feet, what is the Solidity ?

10 - 6 = 43 = 16 ÷ 3 = 5.333 sq. of difference of ends; and 10 X 6 + 5 333 =.65.333 X .7854 x 12 = 015.75 cubic feet the Solidity.

Fig. 14.