MATHEMATICS 9 



As another example, convert 19.635 Kg. into pounds. Work- 

 ing according to the explanation just given, it is 

 found that 19.635 Kg. = 43.2879 Ib. 22.046 



The only difficulty in applying these tables lies 19.842 

 in locating the decimal point; it may always be found 1.3228 

 thus: If the figure considered lies to the left of the .0661 

 decimal point, count each figure in order, beginning .0110 



with units (but calling units' place zero), until the 



desired figure is reached, then move the decimal 43.2879 

 point to the right as many places as the figure being 

 considered is to the left of the unit figure. Thus, in the first 

 example, 8 lies three places to the left of 1, which is in units' 

 place; hence, the decimal point is moved three places to the 

 right. By exchanging the words right and left, the statement 

 will also apply to decimals. Thus, in the second example, 

 the 5 lies three places to the right* of units' place; hence, the 

 decimal point in the number taken from the table is moved 

 three places to the left. 



MATHEMATICS 



MENSURATION 



In the following formulas, unless otherwise stated, the letters 

 have the meanings here given. 



D = larger diameter; 



d = smaller diameter; 



R = radius corresponding to D; 



r = radius corresponding to d; 



p = perimeter or circumference; 



C = area of convex surf ace = area of flat surface that can be 

 rolled into the shape shown; 



5 = area of entire surface = C+ area of the end or ends; 



.4 = area of plane figure ; 



ir = 3. 1416, nearly = ratio of any circumference to its diam- 

 eter; 



V = volume of solid. 



The other letters used will be found on the illustrations. 



