Question

what is true about the number of sides in any regular polygon that has at least one line of symmetry passing through two vertices

Answer 1

Explanation:

A regular n-sided polygon has n lines of symmetry. If n is odd, each line of symmetry passes through only one vertex. If n is even, half the lines pass through two vertices, and half pass through none.

So if a line passes through two vertices, the polygon must have an even number of sides.