x1+x2=500 
x2-x1=256 

x1 = 122 m 
x2 = 378 m 

S1 = 7 m 
Clearance of the lowest point O from water level = 23 m 
The distance from the lowest point to the midpoint = 128 m 
Sag at midpoint = 7.68 m 
Clearance of mid point from water level = 30.70 m 


