Question

What is the first step in describing what figure results when a given plane intersects a given three-dimensional figure?

Answer 1

The first step in describing the result is to determine first how the plane and the figure intersects. :)

Explanation:

Answer 2

There are three possible results when a plan intersects with a three-dimensional figure and these are:
a point
a line
a plane

The first step in describing the result is to determine first how the plane and the figure intersects.