For each of the above sizes find the weig material being wrought iron weighing .278 31. If a water tank 6 ft. inside diam. and 8 what pressure is produced on the supportin weight of water alone? 32. Find the weight of a 20-ft. hollow, column if the outside and inside diamet respectively. 33. A steel shaft weighing 844.46 lb. has a is its diameter? 34. Twenty 3%-in. holes are drilled i How much will the holes reduce the weigh 35. Find the height of a cylindrically diam. to hold 7480 gal. 36. What is the length of a steel shaft 2 ing 108 lb.? 37. What is the volume in cu. in. a steam cylinder 24 in. × 30 in.? 44. Board and Timber Measure. and sold by the thousand boar words, the number cubic feet multiplied Lumber usually co feet, such as 12, 14, in. in thickness is c up the bill. In estimating the given job the calcu One "square" being Shingles are cut 16 i from 4 in. to 6 in. e sold in bundles of 2 shingle is counted as to 6 in. exposed to PROBLEMS 38. Find the number of board feet in a ti wide, and 3 in. thick. -140" 18'0" 28'0" 200 FIG. 103. 39. How many board feet in a timber 16 widths at its ends of 10 in. and 14 in.? 40. Find the amount of lumber required 20 ft. by 14 ft. allowing 10% for waste? 41. It is desired to build a shop fence 8 ft The boards are to be of 1-in. material and a 4-in. rails. How many thousand board feet allowing 10% for waste? shingles 100 sq. ft. 135 sq. ft. 158 sq. ft. a timber 18 ft. long, 10 in. 10 joists, 2 in. x 8 i 4 joists, 3 in. x 8 i 500 feet hemlock she 10 bundles laths at 4 floor beams, 2 thousand. 45. Find the cost of she at $28 per M.B.F., allowin 12% for waste. The calcul and roof. 16 ft. long, 2 in. thick and ed to lay a floor in a room 8 ft. high and 500 ft. long. GENERAL EXPRES 45. Use of Letters to represent becomes convenient in mathemati numbers or the amount of an unk jects by letters of the alphabet in ac figures. The letters of the alphab symbols of numbers to which any be given. Thus, we know the circumference 3.1416 multiplied by its diamet write 3.1416 multiplied by D Here C represents the circumferenc of the circle and both are general sizes of circles. In any problem, understood to have the same problem. The quantity which a called the value of the letter, or its The signs used in connection wit addition, subtraction, multiplicat ing and square root are the same used in arithmetic. 46. The Sign of Addition [+]. "plus." Thus, 3 + 2 is read indicates that the number 2 is to b read "a plus b" and indicates th be added to a. |