Angles

An angle is formed by two rays with a common endpoint called the vertex.

Angle Types

• Acute Angle: Measures less than 90°.
• Right Angle: Measures exactly 90°.
• Obtuse Angle: Measures more than 90° but less than 180°.
• Straight Angle: Measures exactly 180°.
• Reflex Angle: Measures more than 180° but less than 360°.

Angle Measurement

Angles are measured in degrees (°).

Angle Pairs

• Complementary Angles: Add up to 90°.
• Supplementary Angles: Add up to 180°.
• Vertical Angles: Opposite angles formed by intersecting lines, congruent.

Angle Notation

Angles are typically represented by a three-letter notation, e.g., ∠ABC.