264 



PRACTICAL MATHEMATICS 



Find for each mid-ordinate the corresponding points on the de- 

 rived figures (Fig. 83) , and in this way the corresponding mid- 

 ordinates of the derived figures can be found. 



Breadth of strip = 0-6" 



Area of figure = 63-52 x 0-6 = 38-12 sq. in. 



Area of first derived figure = 32-01 x 0-6 = 19-21 sq. in. 



Area of second derived figure = 19-76 x 0-6 = 11-86 sq. in. 



19-21 

 X 3802 

 = 3-024 in. 



I ox = 6 2 x 11-86 



= 427-2 inch units 



Dividing the irregular figure into 10 vertical strips (Fig. 84), 

 and working in the same way with the mid-ordinates of these strips : 



