Answer:
1/21
Step-by-step explanation:
11 boys + 10 girls = 21 students
We want the ratio of coaches to students
1 coach: 21 students
1/21
 
        
                    
             
        
        
        
<em>π</em> ≈ 3.14 > 2, so the second piece is the relevant one:

 
        
             
        
        
        
There is no picture given so I can’t see what the triangle is
        
             
        
        
        
I think it's the distributive property. I'm not sure. But I hope this helps.