| A | B |
|---|
| The segments that form a triangle are called its | sides |
| The endpoints of the sides of a triangle are called | vertices |
| The triangle with vertices R, S, and T is called | the triangle RST |
| You can classify triangles by their | sides and angles |
| A triangle that has no congruent sides | scalene |
| A triangle that has at least two congruent sides | isosceles |
| A triangle that has three congruent sides | equilateral |
| A triangle that has three congruent angles | equiangular |
| A triangle that has three angles less than 90 degrees | acute |
| A triangle that has one angle that measures exactly 90 degrees | right |
| A triangle that has one angle greater than 90 degrees but less than 180 degrees | obtuse |
| The sum of the angle measures of a triangle is | 180 degrees |
