Shapes

Plane Geometry is the study of flat shapes that you see in pictures or on paper. These shapes include lines, circles, triangles, squares, and rectangles. We call them flat because they have length and width, but no thickness.

A side is a straight edge of a shape.

A vertex (more than one: vertices) is a point where two sides meet.

We can classify shapes by looking at how many sides and vertices they have. The table below shows some common flat shapes.

Name	Shape	Number of sides	Number of vertices
Circle		0	0
Triangle		3	3
Square		4 (all the same length)	4
Rectangle		4 (2 long, 2 short)	4