acute triangle	A triangle with three angles that each measure between 0º and 90º.
congruent	Having the same size and shape.
corresponding angles	Angles of separate figures that are in the same position within each figure.
corresponding sides	Sides of separate figures that are opposite corresponding angles.
equilateral triangle	A triangle with 3 equal sides.
isosceles triangle	A triangle with 2 equal sides.
obtuse triangle	A triangle with one angle that measures between 90º and 180º.
polygon	A closed plane figure with three or more straight sides.
right triangle	A triangle containing a right angle.
scalene triangle	A triangle in which all three sides are a different length.
similar	Having the same shape but not necessarily the same size.
triangle	A polygon with three sides.