Volume of the pyramid:

Perimeter of the cross-section:


Area of the cross-section:


First derivative test:

Then the height of the cross-section/pyramid is

The volume of the pyramid that maximizes the cross-sectional area  is
 is

 
        
             
        
        
        
This is what I get not sure if the problem on numerator is together if it is then .  X^2+(a^2+1)     x^2+a^2+1.    
-----------------= -----------------   AX+1.                Ax+1  Answer: a^2+x^2+1               ----------------                 AX+1
If I wrote the actual problem wrong let me know. This is what I understood.
 
        
             
        
        
        
Answer:
It is a rational number
Step-by-step explanation:
It is a rational number because -6/7 is equal to -0.857142 repeating. And a rational number repeats. 
Hope this helps☝️☝☝
 
        
                    
             
        
        
        
Okay i believe the first one is 4/7 and the second one is 2. also don’t listen to them. sometimes it can be hard and you start to stress. good luck and if this isn’t right i’m so sorry :) keep your head up!!!