25 is the length of x, using the 30-60-90 special triangle method 
 
        
             
        
        
        
5/6 is closest to 1 because it it 1/6 away from 1 and is 5/6 away from 0 and is 2/6 away from 1/2 (referring 1/2 as 3/6) Hope this helps!
        
             
        
        
        
1)t=S/U=2.4/12=0.2
2)t=S/U=8.4/36=0,23
3)0.23-0.2=0.03
        
                    
             
        
        
        
B=t-am is the correct answer:)