306 ARITHMETIC 



The number of linear yards of carpet border required 

 for a room is equal to the perimeter of the room in 

 yards. 



EXAMPLE. How many yards of border will be required 

 in carpeting a room 42 ft. long and 26^2 ft. wide? 



SOLUTION. Perimeter of room = 42X2+26X2 = 137 ft. 



137 

 =-3- = 45| yd. 



BOARD MEASURE 



In measuring" lumber, the unit is the board foot, which is a 

 board 1 ft. long, 1 ft. wide, and 1 in. (or less) thick. One 

 board foot is equal to ^ cu. ft. 



Rule. To find the number of board feet in any piece of lumber, 

 multiply the length in feet by the breadth in feet, and this product 

 by the thickness in inches, if it be more than 1 inch; or, otherwise, 

 multiply the length in feet by the breadth in inches, and this 

 product by the thickness in inches, and then divide by 12. 



EXAMPLE. How many board feet are contained in a 

 joist 18 ft. long, 14 in. wide, and 12 in. thick? 



SOLUTION. 18*14X12 = ^ ^^ f ^ 



Lumber is sold by the thousand (M) feet, the term foot 

 being always used instead of the longer term, board foot. 



Rule. To find the cost of lumber, divide the number of feet by 

 1,000 and multiply by the cost per M. 



EXAMPLE. What will be the cost of 19 boards 14 ft. 

 long, 15 in. wide, and \y 2 in. thick, at $23.50 per M? 



SOLUTION. Number of thousand feet = 



=.498f. Hence, .498f X $23.50 = $11.72. 



Shingles are sold in bundles of 250 (J4 M). The lengths 

 of all shingles in bundle are the same (usually 12 in., 

 14 in., or 16 in.), but their widths vary. The average 

 width, however, is generally 4 in., the width of all 

 bundles being alike. When laying shingles, 4 in. is 

 usually exposed to the weather, the remaining portions 

 being concealed by the other shingles. 



