the first two are correct, but the answer for c should be 125
 
        
                    
             
        
        
        
Remark
All Cavaliere's principle says is that a slanted cylinder (for example) has the same volume as a cylinder with perpendicular parallel lines that the cylinder is sitting on.
I little known or maybe not a well emphasized fact is that the base is the same all the way up the cylinder. The coin picture below shows that. The basic formula for a Cavaliere cylinder is the same as for an ordinary cylinder.
See picture below
Formula
V = B * H 
Sub and Solve
V = 1024
r = 8
p=3.14
V = pi*r^2 * h
1024 = 3.14*8^2 * h    combine the right side.
1024 = 3.14*64 *h       
1024 = 200.96 * h       divide by 200.96
1024/200.96 = h
You are only getting 5 inches. 
None of your answers work.The conversion to meters is going to give you an even smaller number. If you add a comment, I'll come back and edit this question.
 
        
        
        
Answer:
let's start with 
6a<42
a<7
Next we simplify
a+4>7
a>7-4
a>3
Step-by-step explanation:
Answer 
3<a<7