An angle less than 90
acute
Triangle with 2 equal angles
Isosceles
Angle between 180 and 360
reflex
triangle with one right angle
right triangle
angle that is equal to 180
straight
triangle with all sides equal
equilateral
Angle greater than 90 and less than 180
obtuse
triangle with no sides equal
scalene
triangle with all acute angles
acute triangle
angle equal to 90
right
triangle contains one obtuse angle
Obtuse triangle
2 angles that share a common vertex and side
adjacent
2 angles whose sum is 90
complementary