Maths ( identifying and measuring angles)

• What is the point where two lines meet in an angle called?


  The point is called the vertex.
• Why are angles important in geometry?


  Angles are used to describe the amount of rotation between two lines.
• How are angles used in geometry?


  To describe the amount of rotation between two lines
• In triangle ABC, what is the vertex of the angle formed at point B?


  Point B
• What is the vertex of angle XYZ where Y is the meeting point of the two lines?


  Point Y
• What are the main types of angles based on their measure?

  1. Acute angle: less than 90°
  2. Right angle: exactly 90°
  3. Obtuse angle: more than 90° but less than 180°
  4. Straight angle: exactly 180°
  5. Reflex angle: more than 180° but less than 360°
• What type of angle is formed by measuring 135°?


  Obtuse angle
• How many degrees are in a full rotation?


  360°
• In what unit are angles typically measured?

  Degrees (°)
• What is a quarter rotation in degrees?


  90°
• What is half a rotation in degrees?


  180°
• Why are there 360 degrees in a full circle?


  It is based on the ancient Babylonian sexagesimal system
• What are other units for measuring angles besides degrees?

  Radians and gradians
• How do you find one-third of a full rotation in degrees?


  By dividing 360° by 3, which equals 120°
• How do you find one-quarter of a full rotation in degrees?


  By dividing 360° by 4, which equals 90°
• What should you align with one arm of the angle when using a protractor?


  The 0° line of the protractor
• If you estimate an angle is slightly larger than a right angle, what range would you expect?


  Between 90° and 120°
• If an angle appears to be about half of a right angle, what range would you expect?

  Between 40° and 50°