Question

a regular pyramid has a regular polygon base and a ____ over the center of the base.
a. congruent polygon
b. perpendicular line segment
c. circle
d. vertex

Explanation:

A regular pyramid is defined as having a regular polygon base and a vertex that is directly over the center of the base. This vertex is the apex of the pyramid. Options A (congruent polygon) doesn't fit as the top of a pyramid isn't another polygon. Option B (perpendicular line segment) is not the correct geometric term for the top - most point. Option C (circle) is not relevant as the base is a polygon, not related to a circle in this context. So, the correct answer is D (vertex).

Answer:

D. vertex