| A | B |
|---|
| an angle less than 90 degrees but greater than 0 degrees | acute angle |
| an angle greater than 90 degrees but less than 180 degrees | obtuse angle |
| an angle that measures 180 degrees and looks like a straight line | straight angle |
| an angle that measures 90 degrees | right angle |
| 2 angles whose sum equals 90 degrees | complementary angles |
| 2 angles whose sum is equal to 180 degrees | supplementary angles |
| a triangle that has all angles less than 90 degrees | acute triangle |
| a triangle that has one angle equal to 90 degrees | right triangle |
| a triangle that has one angle greater than 90 degrees | obtuse triangle |
| a tool used to measure angles | protractor |
| the angles inside any shape or inbetween the lines | interior angles |
| the angles created outside the shape | exterior angles |
| a triangle with all 3 sides of equal length | equilateral triangle |
| the measure of each angle in an equilateral triangle | 60 degrees |
| a triangle with 2 or more equal sides | isosceles triangle |
| a triangle with no equal sides | scalene triangle |
| any closed figure with at least 3 sides | polygon |
| 2 special intersecting lines that cross each other to form 90 degree angles | perpendicular lines |
| 2 lines that cross each other | intersecting lines |
| 2 lines that are always the same distance apart and will never meet | parallel lines |
| the point halfway between 2 endpoints | midpoint |
| a specific location in space | point |
| part of a line that has one endpoint and goes on in one direction forever | ray |
| part of a line that has 2 endpoints | line segment |
| a set of points along a straight path that travels in two directions forever | line |
| term used to describe a shape whose angles are all congruent | equiangular |
| Triangles are classified by their | angles and sides |
| having the same size and shape | congruent |
| a closed figure made of at least 3 straight lines that don't cross each other | polygon |
| any polygon with 4 sides | quadrilateral |
| a parallelogram containing right angles | rectangle |
| a parallelogram containing 4 congruent sides | rhombus |
| a parallelogram with 4 right angles and congruent sides | square |
| a quadrilateral with 1 set of parallel lines | trapezoid |
| a trapezoid with congruent legs | isosceles triangle |
| a quadrilateral with no sets of parallel lines | trapezium |
| a special trapezium containing adjacent congruent sides | kite |
| a polygon with all sides and all angles congruent | regular polygon |
