Answer:
AECG
Step-by-step explanation:
1 
sqrt(49) = 7
sqrt(a^2) = a
sqrt(b^2) = b
For every two variables you can take one out from under the root sign and thorough the other one away.
Answer: E
2
sqrt(36) = 6
sqrt(a^2) = a  See comment for 1.
b must be left where it is. There is only 1 of them.
6asqrt(b)
Answer: A
3. sqrt(25) = 5
sqrt(b^2) = b
a must be left alone.  There's only 1 of them. 
5b sqrt(a)
answer: C
4
sqrt(81 a b)
sqrt(81) = 9
The variables must be left alone. There's only1 of them
9 sqrt(ab)
Answer G
 
        
             
        
        
        
Answer:
A - 144
Step-by-step explanation:
everything else would be too far
 
        
             
        
        
        
For a better understanding of the answer given here, please go through the diagram in the attached file.
The diagram assumes that the base of the hexagonal pyramid is an exact fit (has same dimensions as the face of the hexagonal prism).
As can be seen from the diagram, the common vertices are A,B,C,D,E,F which are 6 in number.
The bottom vertices are G,H,I,J,K,L, which, again are 6 in number.
The Apex of the pyramid, P is one more vertex.
Thus, the total number of vertices in a Hexagonal pyramid is located on top of a hexagonal prism will be the sum of all these vertices and thus will be:
6+6+1=13
 
        
             
        
        
        
It would be D
Hope this helps! :)
~Zain
        
                    
             
        
        
        
Using rigid motion, both of these triangles will be congruent. The reason is because rigid motions include reflections, translations, and rotations. 
None of these transformations will affect the size or shape of the figure, therefore keeping them congruent.