Polygons
An Introduction to Polygons

Shape	Classification
	Triangle 3 sides Tri means three * There are some special triangles that are important to know: Equilateral: All three sides are the same length and all three angles are equal. Isoceles: Two sides have the same length, the angles opposite the equal sides are equal. Scalene: NO two sides have the same length and no two angles are equal. Acute: All three angles are less than a right angle. Obtuse: One angle is greater than a right angle. Right: One angle is 90 degrees - a right angle.
	Quadrilateral 4 sides Quad means four * There are some special quadrilaterals that are important to know: Parallelogram: the opposite sides are parallel. The angles are also equal. Rectangle: all the angles are right angles. Square: all four sides are equal. Rhombus: all four sides are equal, it looks like a square on a slant. Trapezoid: two sides are parallel and two sides are not parallel.
	Pentagon 5 sides Pent means five
	Hexagon 6 sides Hex means 6
	Octagon 8 sides Oct means 8
	Decagon 10 sides Dec means 10

These shapes are only examples, there are several different shapes that can apply to these polygons.
Related Links:
Measuring area and perimeter of shapes.
Geometry Tutorials