| A | B |
|---|
| acute angle | an angle with a measure greater than 0 degrees and less than 90 degrees |
| adjacent angles | angles that are next to each other; they have a common side |
| congruent | having exactly the same shape and size |
| diameter | a line segment that passes through the center of a circle |
| equilateral triangle | all three sides are the same length |
| obtuse angle | an angle with a measure greater than 90 degrees and less than 180 degrees |
| radius | a line segment from the center of a circle to any point on the circle |
| right angle | an angle with a measure of 90 degrees |
| tessellation | an arrangement of shapes that covers a surface completely without overlaps or gaps. |
| tiling | another name for tessalations |
| vertical angles | when two lines intersect, the angles that do not have a common side; have equal measures |
| opposite angles | another name for vertical angles |
| scalene triangle | a triangle whose sides all have different lengths; all 3 angles are also different |
| isosceles triangle | a triangle with two sides with equal lengths; 2 angles are also equal |
| equilateral triangle | a triangle with all sides equal and three 60 degree angles |
| right triangle | a triangle with one right angle |
| similar figures | figures that have exactly the same shape |
| the sum of the angles of a triangle | 180 degrees |
| the sum of the angles of a quadrilateral | 360 degrees |
