Leah, she ran farther by 1/21
How you get the answer: 
5/7 
Multiply 7x3 to get the denominator and do the same to the numerator 5x3! Which is 15/21
To get 21 from 2/3 is to multiply 3x7 (denominator) and 2x7 (numerator) to get 14/21
15/21 > 14/21 so Leah ran farther by 1/21
        
             
        
        
        
The missing measure is 26.13............
        
                    
             
        
        
        
Answer:
I think I got it right! I think it's x=4
if not I'm sorry :(