| A | B |
|---|
| parallel lines | lines that will never touch |
| perpendicular lines | lines that cross and make a right angle (90) |
| intersecting lines | lines that cross |
| scalene triangle | triangle with all 3 sides different |
| isoceles triangle | a triangle with 2 sides the same length |
| equilateral triangle | triangle with all 3 sides the same |
| quadrilateral | a polygon with 4 sides |
| parallelogram | a quadrilateral with 2 pairs of parallel lines |
| rectangle | a quadrilateral with 2 pairs of parallel lines, 4 right angles, and opposite sides the same length |
| square | a quadrilateral with 2 pairs of parallel lines, 4 right angles, and all sides the same length |
| trapezoid | a quadrilateral with 1 pair of parallel lines |
| pentagon | a polygon with 5 sides |
| hexagon | a polygon with 6 sides |
| heptagon | a polygon with 7 sides |
| octagon | a polygon with 8 sides |
| nonagon | a polygon with 9 sides |
| decagon | a polygon with 10 sides |
| symmetry | take a polygon, fold it in half, and both sides are the same |
| congruent shapes | exactly the same size and shape |
| acute angle | angle with less than 90 degrees |
| obtuse angle | angle with more than 90 degrees but less than 180 degrees |
| right angle | angle that measures exactly 90 degrees |
| vertex | the end point of an angle |
