Types and Classifications of Angles

This video tutorial introduces the concepts of right, acute, and obtuse angles. Right angles are exactly 90 degrees and are marked by a small box at the vertex. Acute angles measure less than 90 degrees, while obtuse angles are between 91 and 179 degrees. The video explains how to identify each type of angle and provides visual cues for recognition. It concludes with a summary of the differences between these angles.

What is a defining feature of a right angle?

• It measures exactly 180°.

• It looks like an L and has a small box at the vertex.

• It is larger than 90° but smaller than 180°.

• It is any angle smaller than 90°.

Which of the following angles is considered acute?

• 90°

• 95°

• 45°

• 180°

An angle measuring 89° is classified as:

• Obtuse

• Straight

• Acute

• Right

What is the range of degrees for an obtuse angle?

• 91° to 179°

• 180° to 360°

• 1° to 89°

• 90° to 180°

Which angle is NOT obtuse?

• 120°

• 135°

• 150°

• 90°

An angle measuring 100° is:

• Acute

• Right

• Obtuse

• Reflex