Suppose a well is 40 feet deep, and 5 feet in diameter, required the number of cubic feet, or yards?

5 X 5 = 25 X .7861 = 19.635 X 40 = 785.4 cubic feet.

Suppose a well to be 4 feet 9 inches diameter, and 16½ feet from the bottom to (he surface of the water; how many gallons are therein contained?

4.752 X 16.5 X 5.875 = 2187152 gallons.

Again, suppose the well's diameter the same, and its entire depth 85 feet; required the quantity in cubic yards of material excavated in its formation.

4.752 X 35 X 02909 = 22.972 cubic yards.

A cylindrical piece of lead is required 7½ inches diameter, and 168 lbs. in weight; what must be its length in inches?

7.52 X 8223 = 18, and 168 / 18 = 9.3 inches.