LAND MEASURE 



39 



7. The specific gravity of oak is .75, of poplar .45, of 

 white pine .4. Compare the weights of a sill of each 12 ft. 

 long, 12 in. wide, and 10 in. thick. 



8. If a cubic foot of water weighs 62.5 lb., and the specific 

 gravity of ice is .92, what is the weight of a cubic foot of ice ? 



9. If a gallon of water weighs 8.35 lb., and the specific 

 gravity of milk is 1.03, what is the weight of a gallon of 

 milk? 



10. If a gallon of water weighs 8.35 lb., and the specific 

 gravity of oil is .9, what is the weight of the oil in a barrel 

 holding 40 gal. ? 



LAND MEASURE 



44. A rectangular field is one bounded by four straight 

 lines, having four square corners. An acre contains 160 sq. rd. 



EXERCISE 



1. Lay off a square rod on the school yard, and mark 

 with 4 firmly set stakes. 



2. Lay off an acre of land in the form of a rec- 

 tangle near your schoolhouse, and mark with stakes. 



Area = Length rimes width 



Length 



RECTANGULAR FIGURE 



3. How many acres are there in a rectangular field 80 rd. 

 long by 60 rd. wide ? 



4. What must be the width of a rectangular field 80 rd. 

 long to contain 25 A. ? 



