Volume of triangular cross section = (L x B X H )
= (20 x 12 x6)
Depth = 4m
Here Displacement means = displacement by triangular cross section.
In triangle ABC, CG is perpendicular to AB
So triangle GBC and EFC are similar,
So by law of similar angle triangle
GB / EF = GC / EC
6 / EF = 6/ 4
EF = (6x 4)/6
Now, DF = (2EF)
Displacement = ( u/w volume ) x (1.025)
= (20 x 8 x 4) x (1.025)
= 656 t .