The Second Dimension 2-D Shapes Before we get to 3-D figures like prisms or pyramids we need to learn about two-dimensional shapes Two-dimensional 2-D shapes have two measureable dimensions length and width but no thickness Each 2-D shape is located on a flat plane If you are thinking about airplanes then you have the wrong planes A plane is a flat surface that extends forever in all directions It has no thickness You can think of it as a flat floor Many video games use planes as the surface for your favorite video game characters to roam around on 4
Some examples of two-dimensional shapes include triangles squares and circles 5
Polygons are closed two-dimensional figures that consist of only straight lines Polygons Nonpolygons 6
Remember to be a polygon the shape needs to be closed flat have no curves B Polygon Nonpolygon A C Polygon Nonpolygon D Polygon Nonpolygon C Polygon D Nonpolygon A Nonpolygon B Polygon Answers Polygon Nonpolygon 7
