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Lesson 8: Names of Basic Shapes
It's important to know the names of various two-dimensional shapes. These names come up frequently on exams. Later you'll learn more about these shapes.
Don't forget to watch the embedded YouTube video clip for this lesson at the bottom of the page.
This is a topic that needs to be memorized. Take a look at the two-dimensional (flat) shapes below, and make sure that you learn their names. Note that the pentagon has 5 sides, just like our government building, and a hexagon has 6 sides. An octagon, which we see every day on stop signs, has 8 sides.
Closed shapes with all straight sides are called polygons. That just means "many sides." A regular polygon is a shape in which all the sides are of equal length. Shapes that have any curves in them are not polygons.
These are the most common shapes, aside from parallelograms, trapezoids, and rhombuses, which you'll learn about later. You might come across shapes of other numbers of sides. Some of them include a heptagon (7 sides), nonagon (9 sides), decagon (10 sides), hendecagon (11 sides), dodecagon (12 sides), triskaidecagon (13 sides), and icosagon (20 sides). Some of these unusual shapes have alternate names that are considered acceptable. Don't worry about memorizing the names of those unusual shapes. Just be sure to know the names of the basic, common shapes like those pictured above.