| A | B |
|---|
| Point | an exact location in space |
| Line | a straight path of points that goes on and on in two directions |
| Plane | an endless flat surface |
| Parallel lines | lines that never intersect |
| Intersecting Lines | lines that pass through the same point |
| Perpendicular Lines | lines that form right angles |
| Line segment | a part of a line with two endpoints |
| Ray | a part of a line that has one endpoint and continues forever in one direction |
| Angle | a figure that is formed by two rays that have the same endpoint |
| Right angle | an angle that is 90 degrees |
| Acute angle | an angle that is less than a right angle |
| Obtuse angle | an angle that is more than a right angle but less than a straight line |
| Straight angle | an angle that forms a straight line |
| Degree | the unit of measure for an angle |
| Unit angle | an angle that cuts off 1/360 of a cirlce and measures 1 degree |
| Protractor | a tool that is used to measure angles |
| Polygon | a close plane figure made up of line segments |
| Side | a line segment that is part of a polygon |
| Vertex | the point where two sides of a polygon meet |
| Triangle | a 3-sided polygon |
| Quadrilateral | a 4-sided polygon |
| Pentagon | a 5-sided polygon |
| Hexagon | a 6-sided polygon |
| Octagon | an 8-sided polygon |
| Equilateral Triangle | a traingle with 3 equal sides |
| Isosceles triangle | a triangle with 2 equal sides |
| Scalene triangle | a triangle with no equal sides |
| Right triangle | a triangle with one right angle |
| Acute triangle | a triangle with all acute angles |
| Obtuse triangle | a triangle with one obtuse angle |
| Rhombus | a quadrilateral with opposite sides that are parallel and all sides equal in lenght |
| Trapezoid | a quadrilateral with only one pair of parallel lines |
| Parallelogram | a quadrilateral that has 2 pairs of parallel lines |
| Rectangle | a quadrilateral with 4 right angles |
| Square | a quardrilateral with 4 equal sides and 4 right angles |
| Symmetric | when a shape can be folded on a line to form two equal halves that fit on top of each other |
| Line of symmetry | the fold in a symmetric shape |
