Which of these shapes are polygons and which are not and why?

1, 2, 3, 4 are examples of polygons

Step-by-step explanation:

First, let's take a look at what a polygon is. A polygon is a 2-dimensional shape formed by straight lines that are enclosed with 3+ sides in my own words.

Shape 1 : Yes, all sides are straight and closed.

Shape 2 : Yes, straight and closed.

Shape 3 : Yes, straight and closed.

Shape 4 : Yes, straight and closed. For the last time.

Shape 5 : Uh... yeah it's not even a shape it's 3 lines.

Shape 6 : I mean, it's missing a side to close it up.

Shape 7 : Enclosed, right. But there are 2 different shapes in 1.

180°

step-by-step explanation:

sum of equilateral triangle=180°

< n=60°

< m=120°°[angle supplementary of equilateral angle]

< m+< r+< x=360°(sum of exterior angle of triangle)

step-by-step explanation:

gym b charges $1.05 less per hour than gym a.