LAWS OF DECREMENT. 379 



Here the angle - 

 /, = 105 5' 

 7 2 = 74 55' 

 A. 101 55'. 



We have seen that cos. * A =. 



2 sin. i I I 



By means of the tables of logarithms we find the 

 angle A l , thus, 



* ......... = 20* - 



log. 2 ..... = 0-3010300 

 log. sin. /, = 



log. sin. 52 32' 30" = 9-8997088 



-- 10*2007388 



Therefore . . . log. cos. f^, 9-7992612 



Therefore f A t = 50' 57' 30", and consequently 

 A? 101 55'. 



A 2 =78 5' 



A 3 =63 44' 45", which may be found thus from the 



formula. . cos. A = cot 60 cot - * 7 * 



R 



= cot - 60 cot. 52 32' 30' ; 



log. cot. 60 . . . = 9.7614394 

 log. cot. 52 32' 30' ; = 9.8843264 



19.6457658 

 log. R .... 10. 



log. cos. A 3 . . . = 9.6457658 

 Therefore angle A 9 = 63 44' 45 /; . 



