Learn to measure and draw angles using protractors and understand angle types. Master angle measurement through virtual protractor activities.
Scenario: You're in a virtual protractor workshop! You need to measure angles in a building blueprint: a door frame at 90°, a roof slope at 45°, and a decorative arch at 120°. Then you need to draw new angles: 65° for a window frame and 110° for a garden path.
This workshop will teach you how to use a protractor like a pro! You'll learn to measure existing angles and draw new ones with precision.
Angles are classified by their size in degrees. Each type has special properties and uses.
A protractor is a tool for measuring and drawing angles. It has two scales: inner (0°-180°) and outer (180°-360°).
To measure an angle: place the protractor's center on the vertex, align the base line with one ray, and read where the other ray crosses the scale.
Steps: 1) Center on vertex 2) Align base line 3) Read the degree where the second ray crosses
To draw an angle: draw a ray, place the protractor's center on the endpoint, mark the desired degree, and draw the second ray.
Steps: 1) Draw first ray 2) Center protractor 3) Mark degree 4) Draw second ray
Use the inner scale (0°-180°) for most angles. The outer scale (180°-360°) is for angles greater than 180°.
Tip: If the angle looks acute or right, use the inner scale. If it looks obtuse, check both scales.
Practice measuring these angles:
Draw these angles accurately:
1. Classify a 45° angle
2. Classify a 90° angle
3. Classify a 120° angle
4. Classify a 180° angle
5. Measure the angle between 3 o'clock and 6 o'clock
6. Measure the angle between 12 o'clock and 4 o'clock
7. Measure the angle between 2 o'clock and 8 o'clock
8. Measure the angle between 1 o'clock and 7 o'clock
9. A roof has a 30° slope. Is this acute, right, or obtuse?
10. A door opens to 45°. What type of angle is this?
11. A clock shows 2:00. What angle do the hands make?
12. A ladder leans at 75°. Is this safe for climbing?
Wrong: Placing the protractor anywhere on the angle
Correct: Always center the protractor's center point on the angle's vertex
Wrong: Reading from the outer scale when the inner scale is correct
Correct: Use the inner scale (0°-180°) for most angles, outer scale for angles > 180°
Angles are measured in degrees and classified by size
Always center the protractor on the angle's vertex
Use the appropriate scale for the angle size
Practice with real-world examples to build confidence