Equiangular triangle
all sides are congruent
Acute triangle
all angles are acute
Right triangle
one right angle
Obtuse triangle
one obtuse angle
Equilateral triangle
all sides congruent
Isosceles triangle
at least two sides congruent
Scalene triangle
no sides congruent
Exterior angel of a polygon
an angle formed by a side and an extension of an adjacent side
Remote interior angles
two nonadjacent interior angles