Answer:
64pi
Step-by-step explanation:
area= pi * r^2
 
        
                    
             
        
        
        
Answer:
Nocomplanar? Right because they’re not all in the same place?
Step-by-step explanation:
 
        
             
        
        
        
Answer:
so sorry yarr my same question 
I hope you other 
 
        
             
        
        
        
Answer:
6 : 1 
Step-by-step explanation:
b - 3a / 9 = a /3
Cross multiply 
3(b - 3a) = 9a
Expand 
3b - 9a = 9a
Add 9a to both sides 
3b = 9a + 9a
3b = 18a
Divide both sides by 3 
b = 6a 
Ratio of a : b
6 : 1 
 
        
             
        
        
        
So first create and define your variables:
Z = amount of zebra fish
N = amount of neon tetras
Now create your equations:
2z+2.15n=31.20
z+n=15
This is your system. There are multiple methods to use but in this problem I’ll use the substitution method by simplifying the bottom equation.
2z+2.15n=31.20
z=15-n
Now I’ll plug the bottom equation into the top one.
2(15-n)+2.15n=31.20
And just solve from here.
30-2n+2.15n=31.20
0.15n=1.20
n=8
So he bout 8 neon tetras, and 15-8= 7, so he bought 7 zebra fish