Measurement and Types of Angles
Learn about different types of angles and how to measure and draw angles using a protractor. Let's get started! 🚀
Video Lesson
Watch and learn the basics
Flashcards
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🛎️ What is an Angle?
- An angle is formed when two lines meet at a point, called the vertex.
- Angles are measured in degrees (°).
🛎️ Types of Angles
- Acute angle: 0° < angle < 90°
- Obtuse angle: 90° < angle < 180°
- Reflex angle: 180° < angle < 360°
🛎️ How to Measure Angles?
- Place the centre of the protractor on the vertex.
- Align the zero line with one arm and read where the other arm crosses the scale.
🛎️ Measuring Angles Greater Than 180°
- Measure the smaller angle first using the protractor.
- Subtract from 360° to find the reflex angle.
🛎️ How to Draw Angles?
- Draw a straight line for one arm of the angle.
- Place the protractor, mark the required angle, then draw the second arm.
🛎️ Drawing Angles Greater Than 180°
- Subtract the given angle from 360° to find the smaller angle.
- Draw the smaller angle, and the reflex angle is the one you need.
Practice Questions
Test your understanding
What is the measure of a straight angle?
Correct! 🎉 +10 pointsNot quite right
A straight angle forms a straight line and always measures 180°.
Which of these is an acute angle?
Correct! 🎉 +10 pointsNot quite right
An acute angle is greater than 0° and less than 90°. 45° satisfies this.
What is the sum of the angles in a full circle?
Correct! 🎉 +20 pointsNot quite right
A full circle always measures 360°.
Construct a 210° angle using a protractor. What smaller angle should you first draw?
Correct! 🎉 +20 pointsNot quite right
To construct 210°, subtract from a full turn: 360° − 210° = 150°.
An angle measures 110°. What type of angle is it?
Correct! 🎉 +20 pointsNot quite right
An obtuse angle is greater than 90° but less than 180°.
Two angles form a straight line. One angle is 5 times the size of the other angle. What is the measure of the larger angle?
Correct! 🎉 +30 pointsNot quite right
A straight line is 180°. Dividing into 6 equal parts gives 30°. The larger angle is 5 × 30° = 150°.
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