| A | B | 
|---|
| scalene triangle | no sides the same length | 
| isosceles triangle | at least 2 sides the same length | 
| equilateral triangle | all 3 sides the same length | 
| acute triangle | all angles less than 90 degrees | 
| right triangle | one angle equals 90 degrees | 
| obtuse triangle | one angle greater than 90 degrees | 
| congruent triangles | triangles that are the same shape and same size | 
| similar triangles | triangles that are the same shape but may not be the same size |