Which of the following best describes the base of a pyramid?
a. it can be any polygon.
b. it is a circle.
c. it must be a square.
d. it is a triangle.

A. It can be any polygon.

Step-by-step explanation:

A pyramid is a polyhedron with a base, which can be any polygon, but is most often a square.

When the base is a triangle, the pyramid has a total of four faces.

The famous Egyptian pyramids have square bases and four triangular faces. As the number of sides increases in a pyramid, it begins to look like a cone.

So, we can say A and C are both correct. But we will go with A as a square will also be considered in it.

answer:

at time x=0 we have 1000, at time x=1 we have 2000, at time x=2 we have 4000.  

so that's an initial value of 1000 and a ratio of 2,

y = 1000 (2^x)

hope this !