1 lb. 123-9632889-5760 gr. 1 lb. avoirdupois 7000 gr.; 1 oz. avoirdupois = 437 gr. 1 lb. Troy = = 5760 gr. ; 1 1 lb. apothecaries' = 5760 gr.; 1 oz. apothecaries' = 480 gr. ORAL EXERCISE. 1. How many ounces in 6 lb. Troy? In 41⁄2 lb.? 2. How many ounces in 3 lb. 11 oz. Troy? In 10 lb 14 oz.? 3. How many pounds in 49 oz.? In 59 oz.? In 63 oz. 4. How many pennyweights in 4 oz.? In 5 lb.? In 2 lb. 6 oz.? 5. How many ounces in 60 dwt.? In 960 gr.? In 21 lb.? 6. How many scruples in 3 3 23? In 1 lb. 6 3 53? 7. What is the difference in weight between an ounce of gold and an ounce of iron? Let the pupil explain. 3. Reduce 6 lb. 7 oz. Troy to ounces. 4. Reduce 7 lb. 8 oz. 4 dwt. to pennyweights. 5. Reduce 1600 dwt. to pounds, etc. 6. Reduce 9000 gr. to pounds, etc. Ans. 79. Ans. 1844 dwt. Ans. 6 lb. 8 oz. Ans. 1 lb. 6 oz. 15 dwt. 7. How much is a gold chain weighing 1 oz. 3 dwt. worth, at 90 cts. a pennyweight? 8. How many grains in 61⁄2 lb. Troy? Ans. $20.70. Ans. 37440. 9. How many grains in 6 lb. avoirdupois? Ans. 45500. EXTENSION. 97. Extension is that which has one or more of the dimensions-length, breadth and thickness. 98. A Line has length only. 99. A Surface has length and breadth. 100. A Volume has length, breadth and thickness. == 1 mi. = 8 fur. = 320 rd. = 1760 yd. = 5280 ft. = The inch is usually divided into halves, quarters, etc. 63360 in. ORAL EXERCISE. 1. How many inches in 3 ft.? In 5 ft.? 2. How many feet in 24 in.? In 10 ft.? In 60 in.? In 84 in. ? In 40 yd.? In 3 yd. 2 ft. ? In 36 ft.? In 72 in.? In 4 rd.? In 494 ft.? 7. How many inches in 6 ft. 3 in.? In 3 yd. 2 ft. 9 in.? 8. At 40 cents a foot, how much will 20 rd. of fence cost? Hence, 7 yd. 2 ft. 3 in. = 279 in. Hence, 940 in. = 4 rd. 4 yd. 4 in 3. Reduce 16 ft. 5 in. to inches. Ans. 197 in. 4. Reduce 5 yd. 2 ft. 10 in. to inches. Ans. 214 in. 5. Reduce 10 rd. to feet; to inches. 6. Reduce 620 in. to yards, etc. 7. Reduce 720 ft. to rods, etc. Ans. 43 rd. 3 yd. 1 ft. 6 in. Ans. 165 ft. Ans. 17 yd. 8 in. 8. Reduce 800 in. to rods, etc. Ans. 4 rd. 8 in. SURFACE OR SQUARE MEASURE. 102. Square Measure is used in measuring areas or surfaces. 103. A Surface has length and breadth only. 104. A Rectangle is a figure having four sides, each of which is perpendicular to two of the others. A slate, a book and a sheet of paper are examples of rectangles. 105. A Square is a rectangle whose four sides are equal. A square inch is a square whose sides are each one inch long. 106. The Area of a surface is equal to the product of the two numbers representing the two dimensions. Thus, in the rectangle ABCD, 4 5 ft. long and 3 ft. wide, the unit, which is 1 sq. ft., is contained 3×5 times, or 15 times. This may be found also by actual count of the small squares found in the rectangle. D B From this we have the rule to find the area of a rectangle or similar surface: RULE. Multiply the length by the breadth. TABLE. 144 square inches (sq. in.) = 1 square foot, sq. ft. 1 A.-160 sq. rd. = 4840 sq. yd. = 43560 sq. ft. = 6272640 sq. in. ORAL EXERCISE. In 1 sq. yd.? In 5 sq. yd.? 1. How many square inches in 2 sq. ft.? 2. How many square feet in 3 sq. yd.? 3. How many square feet in 3 sq. rd.? 4. How many square yards in 5 sq. rd.? In 90 sq. ft.? 5. How much will 1 sq. mi. of land cost at $50 an acre? WRITTEN PROBLEMS. 1. How many square rods in 2 A. 4 sq. rd.? Ans. 324. 2. Reduce 435600 sq. ft. to acres? 3. How many acres in 3 sq. mi. ? 4. A town-lot is 160 ft. long and 60 ft. square feet does it contain? Ans. 10 A. Ans. 1920 A. wide: how many Ans. 9600. 5. In a rectangular piece of land 480 ft. long and 320 ft. wide, how many acres are there? Ans. 3 A. 84 sq. rd. 51 sq. ft. 6. If I buy 10 A. of land at $150 an acre, and sell it at 2 cts. a square foot, how much do I gain? Ans. $7212. MEASURES OF VOLUME. 107. Cubic Measure is used in computing the con tents of volumes or solids. 108. A Volume or Solid has three dimensions-length, breadth and thickness. 109. A Cube is a volume bounded by six equal squares, which are called its faces. The three dimensions of a cube are equal. A cubic inch is a cube each side of which is one inch in length. |