11. Draw other lines1 2 inches; 3 inches; 6 inches; 5 inches, and 7 inches in the same way and check each by comparison with the ruler.

12. How many inches are there in a yard?

13. Draw a line, freehand, a yard long on the blackboard. Measure with a ruler or a yard stick to see how near a yard it is.

14. Stand, as nearly as you can estimate, a rod from the front wall of the school room. Have some other pupil measure this distance to see how closely you estimated that distance.

15. How many rods wide is the street or road in front of your schoolhouse? Measure this distance in rods to see how correctly you have estimated it.

Exercise 2

1. How many rods are there in a mile? How many feet are there in a rod? Then how many feet are there in a mile? 2. How many yards are there in a rod? How many rods are there in a mile? Then how many yards are there in a mile?

3. Find the number of inches in a rod.

4. Find the number of inches in a mile.

5. Change the following to inches: 13 feet; 2 feet; 3 feet 6 inches; 1 foot 8 inches; 1 yards; 1 yard 4 inches.

6. Change the following to feet: 1 yards; 2 yards; 14 rods; mile; mile; 84 inches; 5 rods; 144 inches.

7. Change the following to yards: 6 rods; 10 rods; 16 feet; 30 feet; 72 inches; mile; mile; mile; 120 feet.

Make cards of various sizes and have pupils estimate the length and width of each as it is held before the class. This gives valuable training in estimating small distances.

8. In a certain city 10 blocks make a mile. How long is each block?

Distances on land are measured very accurately by surveyors. They use a surveyor's chain that is made of 100 links.

9. A surveyor's chain is 66 feet long. Find the length of each link in inches.

10. Caesar's Roman soldiers counted 2000 steps as a mile. If their mile had been exactly the same as ours how long was the average step of these soldiers?

11. In the American army, the marching step for quick time is 2 feet. How many such steps are there in a mile?

12. Walk 20 steps at your natural pace. Measure the distance that you have stepped and find the average length of each step. Some people become very expert in estimating distances by stepping them off. Practice stepping off and estimating distances.1

13. The Eiffel Tower in Paris is 984 feet in height. How many yards high is it? Find its height, expressed as a decimal fraction of a mile.

14. The span of the Brooklyn bridge is 1595 feet. What decimal fraction of a mile is the length of this span?

15. Railroads have their tracks divided into divisions called "blocks." Where the block system prevails no train can enter one of these divisions until the train ahead has left that "block." In a railway distance of 320 miles there are 80 equal "blocks." How long is each of these blocks?

16. Two of the races in a regular track meet are the quartermile and half-mile runs. How many yards are there in each

of these distances?

"The teacher should use local situations for his work.

George and Harold are measuring Harold's garden plot. They find it to be 49.5 feet long and 33 feet wide. What units of measure should they use in describing the area or size of this garden plot?

The areas or sizes of such sur

faces are usually expressed as equal to a certain number of

square units.

This figure is a square. sides compare in length?

How do its four

Since each side of this square is an inch in length, the square is called a square inch.

1. How long is the side of a square foot? 2. How long is the side of a square yard?

3. Draw a square foot on the blackboard.

Mark off the sides into inches and draw lines dividing it into inch squares as shown in the illustration. How many inch squares are there in one row an inch wide along one side? How many such rows are there in the square foot? A square foot, then, is equal to how many square inches?

4. Draw a square yard on the blackboard. Mark off each side of the square yard into square feet and draw lines, dividing the square yard into square feet. How many square feet are there in a row one foot wide along the side? How many such rows are there in a square yard? A square yard, then, is equal to how many square feet?

yards or 16

A rod is equal to 5 feet. A square rod is 5 yards long and 5 yards wide.

In a row 1 yard wide along one side there are 5 square yards. Since there are 5 such rows there are 5×5 square yards which are 301 square yards.

5. Measure on the floor of your school room or on the playground 160 square rods of area are called an acre.1 An acre is the unit used in measuring land areas.

an area of 1 square rod.

Table of Square Measure

144 square inches (sq. in.) = 1 square foot (sq. ft.)
9 square feet=1 square yard (sq. yd).

301 square yards = 1 square rod

160 square rods = 1 acre

Exercise 4

1. Harold's garden plot is 49.5 feet long and 33 feet wide. How many feet are there in a rod? Find the length and width

of his plot in rods.

2. A diagram may be drawn of his garden plot showing how it can be divided into square rods. How many square rods are there in one row a rod wide along one side? How many such rows are there in his plot? He may express the area of his garden plot as equal to how many square rods?

'In the olden time when the plowing was done with the slow and heavy oxen, the amount that a man could plow in a day was called an acre.

3. Harold raised peas and onions on his garden plot and made a profit of $9.24 on his plot of ground. He is measuring the plot to find how large it is so he can figure what his income would have been on an acre of ground. What was his average profit on each square rod of his garden?

4. Find how much he would have received from an acre of ground at that rate.

5. A square mile is how many rods long? How many rods wide? How many square rods are there in a row 1 rod wide along one side of a square mile? How many such rows are there in a square mile? A square mile, then, is equal to how many square rods?

6. How many square rods make one acre? How many acres are there in a square mile?

7. A square rod is 16 feet long and 16 feet wide. By means of a diagram, show how many square feet there are in a square rod.

8. How many square feet are there in an acre?

Suggestion: How many square feet are there in a square (See Problem 7.) How many square rods are there in

rod?

an acre?

9. Lester1 made a profit of $134.04 from his 109 square rods of sweet corn. What was his profit per square rod? How much would he have made on an acre at that rate?

10. Theodore1 had a garden plot that had an area of 4356 square feet. He raised beans which brought $110.75 when sold in the market in the fall. His plot was what fraction of an acre? (See Problem 8.) What was his rate of profit per acre?

11. Ralph has a corn field 8 rods long and 3 rods wide. How many square rods are there in the field?

1From School Achievements, 1916.