13. What is the diameter of a circle, whose circumference is 314.159 ft. 1

629. To find the area of a circle. (Leg. V. 11.)

Multiply half the circumference by half the diameter ; or, mul-
tiply tJte square of the diameter by the decimal .T854.
15. What is the area of a circle, whose diameter is 50 rods ■?

16. Find the area of a circle 200 ft. in diameter, and 628.318 ft. in circum,

630. To find the side of the greatest square that can be in^
scribed in a circle of a given diameter.
Divide the square of the given diameter by 2, and extract the
square root of the quotient. (Art. 581. Obs. 1.)

17. The diameter of a round table is 4 ft. ; what is the side of the greatest
square table which can be made from it 1

631. To find the side of the greatest equilateral triangle that
ean be inscribed in a circle of a given diameter.
Multiply ji the given diameter by 1.73205. (Leg. V. i. Sch.)

18. Required the side of an equilateral triangle inscribed in a circle of S20'fl
^meter.
Arts. 626-637.] mensuration 891

measurement of solids.
632. In the measurement of solids it is customary to assume
a cube as the measurinff unit, whose sides are squares of the same
name. (Art. 258. Obs. 2.)

633; To find the solidity of bodies whose sides are perpen-
dicular to each other.
