Circle
A round shape, drawn like this:
Triangle
A shape with three sides. Sometimes the sides are equal—sometimes they aren’t. Their
names are sometimes different depending on the length of the sides. We will show
you the common ones:
Equilateral triangle—this triangle has 3 equal sides.
Isosceles triangle—this triangle has 2 equal sides.
Scalene triangle—this triangle has no equal sides.
Square
A box shape, with four equal sides—opposite sides are parallel, drawn like this:
Parallel means non-intersecting. For example, parallel lines means that if the two
lines kept going forever, they would never cross over each other—they would always
be an equal distance apart.
Rectangle
Another box shape, with two sets of equal sides. Equal sides are opposite each other.
The sides are parallel to each other. It’s drawn like this:
Trapezoid
Another 4 sided shape, with one set of parallel lines (the other set of lines is
not parallel), drawn like this:
Pentagon
A shape with five sides. They can be drawn many different ways, but these are the
most common:
The pentagon on the left is known as a regular pentagon, because all of its sides
are the same length. The one on the right is also a commonly known pentagon, shaped
like a house.
Hexagon
A shape with six sides, drawn like this:
Heptagon
A shape with seven sides, drawn like this:
Octagon
A shape with eight sides, drawn like this:
You’ll notice that the octagon is the shape they use for stop signs.
Nonagon
A shape with nine sides, drawn like this:
Decagon
A shape with 10 sides, drawn like this:
Dodecagon
A shape with 12 sides, drawn like this:
Polygons
All of these shapes are polygons. A polygon is a shape made of lines that could
be colored in (all the lines meet and it has a “middle”).
Most of what you will be asked to do with these shapes is recognize them and draw
them, so memorize how many sides they have, what they look like, etc. Other things
may include calculating the area and/or perimeter of these shapes. If you’re trying
to find area or perimeter, read our page on
Area and Perimeter.
