If you draw 2 equilateral triangles are congruent and share a side. what polygon is formed? is it a regular polygon?

The polygon formed is rhombus which is regular polygon.

Step-by-step explanation:

Given that if we draw 2 equilateral triangles are congruent and share a side AC as shoen in figure then

we have to tell what polygon is formed it is regular or not.

As two equilateral triangles are congruent it means also the sides of two equilateral triangle are equal.

Also the angles are of 60° which implies the angle formed at intersecting the diagonals at right angle i.e of 90°

Hence, all the properties of rhombus satisfied which implies

The polygon formed is rhombus which is regular polygon.