| A | B |
|---|
| point | a point in space |
| ray | part of a line extending in 1 direction |
| angle | two rays called sides with the same endpoint called a vertex |
| degree | the unit used to measure angles |
| straight angle | an angle measuring 180 degrees |
| obtuse angle | an angle measuring between 90 & 180 degrees |
| intersecting lines | lines that meet |
| perpendicular lines | lines that meet and form right angles |
| triangle | a 3 sided polygon |
| isosceles triangle | a triangle having 2 sides the same length |
| acute triangle | a triangle having 3 angles less than 90 degrees |
| obtuse triangle | a triangle having 1 obtuse angle |
| quadrilateral | a 4 sided polygon |
| rhombus | a parallelogram having 4 sides the same length |
| square | a parallelogram having 4 sides the same length & 4 right angles |
| pentagon | a 5 sided polygon |
| octagon | an 8 sided polygon |
| diagonal | a line segment (not a side) that joins 2 vertices of a polygon |
| congruent | shapes having the same size and shape |
| similar | 2 shapes having the same shape but NOT the same size |
| circle | all the points in a plane that are the same distance from a center point |
| radius | a line segment that has endpoints on the circle |
| central angle | an angle that has its vertex at the center of a circle |
| rotation | to change the position of a shape by turning it on a curved path around a point |
| complementary angles | 2 angles whose sum is 90 degrees |
| line | a straight path extending in 2 directions |
| supplementary angles | 2 angles whose sum is 180 degrees |
| reflection | to change the position of a figure by flipping it along a line of symmetry |
| translation | to change the position of a figure by sliding it along a straight line |
| polygon | a closed figure having sides that are line segments that are named according to the number of sides |
| diameter | a line segment that has endpoints on the circle and passing through the center of the circle |
| chord | a line segment that has endpoints on the circle |
| proportion (equal ratios) | the process for finding the lengths of corresponding sides |
| symmetry | folding a shape so that one half fits exactly over the other |
| line segment | part of a line with 2 endpoints |
| sum of the angles of a polygon | the number of sides -2 times 180 |
| decagon | a 10 sided polygon |
| hexagon | a 6 sided polygon |
| trapezoid | a quadrilateral having exactly 1 pair of parallel sides |
| rectangle | a parallelogram that has 4 right angles |
| parallelogram | a quadrilateral having 2 pairs of parallel sides & 2 pairs of congruent sides |
| 180 degrees | the sum of the angles in a triangle |
| right triangle | a triangle having 1 right angle |
| scalene triangle | a triangle having no congruent sides |
| equilateral triangle | a triangle having all sides congruent |
| plane | a flat surface extending in all directions |
| protractor | a device for measuring angles |
| right angle | an angle measuring 90 degrees |
| acute angle | an angle measuring less than 90 degrees |
| parallel lines | lines in a plane that never meet |
