Measurement and Types of Angles

🎬 Video Tutorial

(0:29) Types of Angles: Angles are classified by size — acute ($<$ 90°), right (90°), obtuse (90° $<$ θ $<$ 180°), straight (180°), reflex (180° $<$ θ $<$ 360°), and full angle (360°).
(1:20) Measuring Angles with a Protractor: Align the protractor’s centre with the vertex and the zero line with one arm. Read where the other arm crosses the scale.
(2:35) Constructing Angles Over 180°: For 210°, draw the smaller internal angle (150°), as 150° = 360° − 210°. The external angle is 210°.