There are 3 types of triangle based on their interior angles: right triangle, obtuse triangle, and acute triangle.
A right triangle has one angle that measures exactly 90°. The two sides that form the right angle are called legs, and the opposite side is called the hypotenuse.
An obtuse triangle has one angle greater than 90°. Because the three interior angles always add up to 180°, the other two angles are each less than 90°.
An acute triangle has all 3 interior angles less than 90°. An equilateral triangle is a special case where all three angles measure 60°.
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