THE CENTROID 219 



= 66 - 49-72 

 = 16-28 



Moment of rectangle PQLK = 12 

 For the whole area, 



Total moment = 16-28 + 12 = 28-28 



28-28 

 = 18^08 



= 1-564 



Or by taking horizontal strips, 



Moment of strip = - x z y 



Total moment 



*' 



If 11 



-if."* 



waf 4 ,, , 

 = I cc n+1 dx 



2 J 2 



H 



/33.137 _ 23-137\ 



na 



2(^T2)L~ J 2 

 1-137 x 2-273 



Then 



2 x 3-137 

 = 28-26 



28-26 

 * = 18^08 



= 1-563 



Example. Find the height of the centroid of the area bounded 

 by the curve y = sin x and the axis of x, between the limits x = 

 and x = TT. 



Area = 1 y dx 

 Jo 



= I sin x dx 



Jo 



= COS X 



Jo 



= (COS 7T 1} 



