236 



PRACTICAL MATHEMATICS 



TT - 1 - 



I AB = - 



m 3 3 m 2 i i m 3 7 



V27 + 2 X W + 12 X 2 X \2/ + 4 



= 7-271 



I OL = 7-271 - 3-25 x (1-058) 2 

 = 3-632 



Evidently I OK = I OL = 3-632 



The axis OX, being an axis of symmetry, is a principal axis, 

 and by means of lines drawn parallel to OX the section can be 

 divided into triangles and parallelograms. 



FIG. 66, 



For the triangle ADE, 



Base = =, height = 7 =, area = - 



A/2 2A/2 8 



3 1 



Distance of centroid from axis OX = 7= + 



19 



V2 6-V/2 6\/2 



1 1 / 1 \ 3 1 / 19 V 



= X X = -I X I 



36 V2 V2V2/ 8 V 6 V2/ 



1 361 



1152 576 

 = 0-628 

 For the parallelogram EDFB 



Base = j=., height = 



area = - 

 2 



