Term | Definition |
polygon | A closed figure made up of line segments |
side | A line segment that forms part of a polygon |
vertex of a polygon | The point where two sides of a polygon meet. |
diagonal | A line segment that connects two vertices of a polygon that are not next to each other. |
triangle | A polygon with three sides. |
quadrilateral | A polygon with four sides. |
pentagon | A polygon with five sides. |
hexagon | A polygon with six sides. |
octagon | A polygon with eight sides. |
decagon | A polygon with ten sides. |
equilateral triangle | A triangle having three sides of the same length. |
isosceles triangle | A triangle with at least two sides having the same length |
scalene triangle | A triangle in which no sides have the same length. |
right triangle | A triangle in which one angle is a right angle. |
acute triangle | A triangle in which all three angles are acute angles. |
obtuse triangle | A triangle in which one angle is an obtuse angle. |
trapezoid | A quadrilateral with exactly one pair of parallel sides. |
parallelogram | A quadrilateral with two pairs of parallel sides. |
rectangle | A special parallelogram with four right angles. |
rhombus | A special parallelogram in which all sides are teh same length. |
square | A special parallelogram with four right angles and all sides the same length. |