Yes it actually is do the math
Answer:
(a) 
Step-by-step explanation:
The question is incomplete. (See comment for complete question).
From the completed question, we have:

--- number of pyramids
Required
An expression for the area of the base
The total base length of the pyramid represents the perimeter of the base.
And since the base is a square, then the following relationship exist.

Where L represents the length of each side.
This gives

Make L the subject

The area of the base is then calculated as:


The dot product will have you multiply the corresponding coordinates and add up the products
v dot w = (6*(-7)) + (7*5) + (-3*2)
v dot w = -42 + 35 - 6
v dot w = -7 - 6
v dot w = -13
Answer: -13