POLAR FORMULJB. I> iHTBQEAT: 1J7 



umcrator of the value of 3 IB 



and the denominator, in like manner, IB 



I/I WW-!* 01V*; 



\Jfyt0 ;<A flM* " "/* 

 SimiUrlv ; , 



centre of grtrity of the arc* com 

 d between two semicirclea Opb and OPB. 



' Ob-c, OB=h\ 

 = i7r; thus 







a-0, 



i 



2 A -HO 



(Sec 7n/f 35). 



Also 



J? 



