Acute angles are the smallest, being between (but not including) zero and 90° Note also that acute triangles are those where all the interior angles are acute.
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Acute angle Less than 90° |
Right angle Exactly 90° |
Obtuse angle Between 90° and 180° |
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Straight angle Exactly 180° |
Reflex angle Between 180° and 360° |
Full angle Exactly 360° |