A polygon.
Triangle is a shape with three sides.
a triangle
A TRIGON , more usually a 'Triangle'.
A triangle.
A shape that has 10 sides (two dimensional) is called a decagon. A shape that has 10 faces (three dimensional) is call a decahedron.
When two sides (called faces) of a 3-dimensional shape meet, they meet at an edge.
A shape with 7 sides is a heptagon
you call a two dimensional shape with six sides a hexagon
A shape with 8 sides is an octagon.
There's no such thing as a two-sided polygon. In order for a shape to be a polygon, it has to have at least three sides.
A regular shape.
It is an irregular shape