| A | B |
|---|
| Acute angle | An angle whose measure is less than 90 |
| Obtuse angle | An angle whose measure is between 90 and 180 |
| Midpoint | ((x1 + x2)/2, (y1 + y2)/2) |
| Supplementary angles | Two angles whose sum is 180 |
| Complementary angles | Two angles whose sum is 90 |
| Collinear | On the same line |
| Coplanar | On the same plane |
| Hypotenuse | Side across from the right angle |
| Adjacent | "next to" |
| Vertical angles | Non-adjacent, congruent angles formed by intersecting lines |
| Parallel lines | Lines in the same plane that never intersect |
| Perpendicular lines | Lines that intersect to form a right angle |
| Skew lines | Lines that are not in the same plane |
| Isosceles triangle | A triangle with 2 congruent sides |
| Equilateral | All sides are congruent |
| Equiangular | All angles are congruent |
| Area of a rectangle | A = bh |
| Area of a triangle | A = 1/2 b h |
| Perimeter | Add the lengths of all the sides |
| Sum of the interior angles in a polygon | S = (n - 2) 180 |
| Sum of the exterior angles for any convex polygon | 360 |
| Slope formula | (y2 - y1) / (x2 - x1) |
| Percent of increase | change / original |
| For 3 lengths to form a triangle, | the sum of the shorter sides must be greater than the longest side |
| To see if 3 lengths form a right triangle, | test to see if a^2 + b^2 = c^2 |
| Sin A | opp/hyp |
| Cos A | adj/hyp |
| Tan A | opp/adj |
| Congruent figures | Same shape and same size |
| Similar figures | Same shape but different size |
| Reflection | Flips it! (Mirror image) |
| Translation | Moves it! |
| Rotation | Turns it! |
| Dilation | Enlarges or reduces it! |
| Units used for perimeter | Linear units (Ex: feet) |
| Units used for area | Square units |
| Units used for volume | Cubic units |
| Faces of a prism | The sides (flat surfaces) |
| Edges of a prism | The segments where the faces meet (the toothpicks) |
| Vertices of a prism | Where the edges meet (the gumdrops) |
| Corresponding angles | Congruent angles (L- shape) |
| Alternate interior angles | Congruent angles (Z-shape) |
| Sum of the angles in any triangle | 180 |
