The above-mentioned three units are used in the measurement of short distances. For greater distances a larger unit is desirable. For such purposes the kilometer, or 1000 meters, is used. It is about of a mile. Weight The unit of weight is the gram, which is the weight of a cubic centimeter of pure water at 4° Centigrade. A decigram is one tenth of a gram. A centigram is one one-hundredth of a gram. A milligram is one one-thousandth of a gram. These units are used in weighing small bodies. For heavier bodies a larger unit is used, namely, the kilogram, which is 1000 grams. The kilogram is about 2.2 pounds. Volume The unit of volume is the liter, or cubic decimeter, and is equal to about 21 pints. Summary The metric units are subdivided decimally. Thus, to express .1 of a meter, .1 of a gram, and .1 of a liter, the Latin prefix deci- is used in each case. Decimeter means of a meter; decigram of a gram; and deciliter of a liter. To express .01 of a meter, gram, and liter, the Latin prefix centi- is used. Thus, centimeter means of a meter; centigram means of a gram, etc. 100 To express .001 of a meter, gram, and liter, the Latin prefix milli- is used, giving rise to the terms millimeter. milligram, etc. As the system is a decimal one, 10 times one unit of any denomination equals one unit of the next higher denomination. To express 10 times a meter, 10 times a gram, and 10 times a liter, the Greek prefix deca- is used in each case, so decameter means 10 meters, decagram means 10 grams, and decaliter means 10 liters. To express 100 times a meter, gram, and liter, the Greek prefix hecto- is used in each case. Thus hectometer means 100 meters; hectogram means 100 grams, etc. To express 1000 times a meter, gram, and liter, the Greek prefix kilo- is used, giving rise to the terms kilometer, kilogram, etc. Inches to centimeters . 2.54000 Centimeters to inches 0.39370 0.03937 Roman numerals are now seldom used except in date inscriptions, in numbering chapters, and upon the dials of timepieces. The letters used and some of their combinations are as follows: When a letter of less value is written after a letter of greater value its value is added to that of the letter of greater value, as in VI, LX, DC. When a letter of less value is written before a letter of greater value its value is taken from that of the letter of greater value, as in IX, XC, CM. A straight line placed horizontally over a letter or combination of letters has the effect of multiplying by one thousand. 1. How many steps does a man take in walking a mile if he advances 30 inches at each step? 2. If a man takes 37 steps for every 100 feet that he advances, what is the length of each step? 3. How many bushels will a bin 8 feet square and 6 feet deep hold? 4. How many bags of two bushels and a half capacity can be filled from 260 bushels? 5. How many gallons will a tank 4 feet 8 inches by 2 feet 10 inches by 1 foot 6 inches hold? 6. The bottom of a rectangular tank is 6 feet square. How deep must it be to hold 1000 gallons? 7. How many cakes of soap 4 inches by 3 inches by 11 inches can be packed in a box whose inside dimensions are 2 feet, 3 feet, and 4 feet? 8. How many cubic yards of earth must be removed in digging a cellar 36 feet long, 26 feet wide, and 8 feet deep? 9. Find the cost of digging a cellar 42 feet long, 28 feet wide, and 6 feet 6 inches deep, at 50 cents a cubic yard. 10. What is the capacity in gallons of a rectangular tank 9 feet square and 8 feet deep? 11. At $1.20 a bushel what is the value of a bin of wheat 16 feet long, 8 feet wide, and 4 feet deep? 12. What is the capacity in gallons of a rectangular tank 12 feet long, 10 feet wide, and 6 feet deep? 13. What must be the width of a lot 200 feet long if its area is one half an acre? 14. If sound travels at the rate of 1100 feet a second, how far distant is a thunderstorm if the thunder-clap is heard 7 seconds after the lightning flash is seen? 15. If William Cullen Bryant was born Nov. 3, 1794, how old was he June 12, 1878? 16. How many years have elapsed since Dec. 22, 1620? 17. If a rug 9 feet by 12 feet is laid on the floor of a room which is 11 feet by 14 feet, how many square feet of floor surface are bare? 18. An inch of rain on a 12-acre ranch amounts to how many gallons of water? |