| A | B |
|---|
| curve | an uninterrupted set of points |
| closed curve | a curve which starts at a point and comes back to that point |
| simple closed curve | a closed curve which does not cross itself |
| geometric figure | any set of points |
| point | an exact location in space; the intersection of a line and a plane |
| line | a straight path that goes without end in both directions |
| line segment | a set of points made up of two points and all the points between them |
| ray | a straight path that has one end and goes without end in the other direction |
| angle | two rays with a common endpoint |
| vertex | an endpoint common to two sides of a polygon or angle |
| plane | a flat surface with no end |
| congruent | figures which are exactly alike (same shape and same size) |
| similar | figures with the same shape but different size |
| intersecting lines | two lines with one point in common |
| parallel lines | lines on a plane which do not intersect |
| perpendicular lines | lines which meet to form right angles |
| skew lines | lines that are not on the same plane |
| diagonal lines | a line segment (other than a side) that joins two vertices of a geometric figure |
| straight angle | an angle that measures 180 degrees |
| right angle | an angle that measures 90 degrees |
| acute angle | an angle that has a measure greater than 0 degrees and less than 90 degrees |
| obtuse angle | an angle that has a measure greater than 90 degrees and less than 180 degrees |
| adjacent angles | angles that are next to each other and share a common side |
| vertical angles | when two lines intersect, the angles that do not share a common side but do have equal measures |
| supplementary angles | two angles whose measures total 180 degrees |
| complementary angles | two angles whose measures total 90 degrees |
| degree | a unit of measurement for angles based on dividing a circle into 360 equal parts |
| protractor | a tool for measuring and drawing angles |
| reflex angle | an angle that has a measure greater than 180 degrees and less than 360 degrees |
| triangle | a polygon with 3 sides and 3 angles |
| quadrilateral | a polygon with 4 sides and 4 angles |
| pentagon | a polygon with 5 sides and 5 angles |
| hexagon | a polygon with 6 sides and 6 angles |
| heptagon | a polygon with 7 sides and 7 angles |
| octagon | a polygon with 8 sides and 8 angles |
| nonagon | a polygon with 9 sides and 9 angles |
| decagon | a polygon with 10 sides and 10 angles |
| parallelogram | a quadrilateral with 2 pairs of parallel sides and opposite sides are congruent |
| rectangle | a parallelogram with 4 right angles |
| rhombus | a quadrilateral whose sides are all the same length |
| square | a rectangle with all sides equal |
| trapezoid | a quadrilateral that has exactly one pair of parallel sides |
| equilateral triangle | a triangle with all 3 sides equal in length and all three angles have the same measure |
| isosceles triangle | a triangle with at least 2 sides that are the same length and at least 2 angles have the same measure |
| scalene triangle | a triangle with sides of 3 different lengths and no two angles have the same measure |
| right triangle | a triangle that has a right triangle |
| acute triangle | a triangle that has 3 acute angles |
| obtuse triangle | a triangle that has one obtuse angle |
| chord | a straight line joining two points on a circle |
| radius | a line segment from the center of a circle to any point on the circle |
| diameter | a line segment that passes through the center of a circle and has endpoints on the circle |
| circumference | the distance around a circle; the perimeter of a circle |
