Geometry Essentials: Angles and Polygons

Front

Acute Angle

Back

Less than 90°

Front

Right Angle

Back

Exactly 90°

Front

Obtuse Angle

Back

Between 90° and 180°

Front

Straight Angle

Back

Exactly 180°

Front

Reflex Angle

Back

Between 180° and 360°

Front

Full Rotation

Back

360°

Front

Complementary Angles

Back

Sum to 90°

Front

Supplementary Angles

Back

Sum to 180°

Front

Adjacent Angles

Back

Share a common side

Front

Vertical Angles

Back

Opposite angles, equal