190 



FARM ARITHMETIC. 



t.600 sq.ft. 



1.600 sq.ft. 



1.600 sq.ft. 



THE AREA Is JUST THE SAME. 



If each were a silo, and you bought the lumber, would there be any difference 

 in quantity required? 



675. What is the distance around (the perimeter of ) a 

 circular silo 20 feet in diameter ? 



Process : Multiply the diameter by 3.1416. 



Note. The number 3.14 as multiplier is sufficiently accurate 

 for most farm work. 



20 X 3.14 = 62.8 feet. Ans. 



676. What is the base area of a circular .silo 20 feet 

 in diameter? 



Process : Multiply the square of the diameter by 0.7854 or the 

 square of the radius by 3.1416 or 3.14. 



20 X 20 X 0.7854 = 314 square feet. Ans. 



677. What is the area of a circular silo 12 feet in 

 diameter? 25 feet? 32 feet? 40 feet? What is the 

 perimeter in .each case ? 



678. What is the diameter of a circular silo having a 

 base or surface area of 1,600 .square feet? 



Process : Divide the area by 0.7854 and take square root of the 

 result. 



1,600 -f- 0.7854 = 2,024 V2,024 " = 45.1 feet, diameter. 



679. What is the circumference or distance around the 

 inside wall of a silo having a surface area of 1,600 square 

 feet? 



680. What is the distance around a square silo con- 

 taining a surface area of 1,600 square feet? 



