On level ground: 
Height of tower = 18 m 

On sloping ground: 
Vertical distance between two towers = 20 m 
From the graph: 
x1 = 75m, x2 = 225m 
S1 = 2.50 m 
S2 = 22.50 m 
Clearance = 10.50 m 
x = 75 m 
Minimum clearance = 8 m 

