Question

a polygon with all sides and angles equal is known as:
a. an open shape
b. a regular polygon
c. an irregular polygon
d. a triangle

Explanation:

A regular polygon is defined as a polygon with all sides and angles equal. An open shape is not a polygon. An irregular polygon has sides and/or angles of different measures. A triangle is a type of polygon but not all triangles have all sides and angles equal (only equilateral triangles do, but the question is about the general term for any polygon with all sides and angles equal).

Answer:

B. A regular polygon