Angle: The space between two rays that meet at a common endpoint (vertex)
Vertex: The common endpoint where two rays meet
Ray: A part of a line that starts at one point and extends infinitely in one direction
Protractor: A tool used to measure and draw angles in degrees
Degree (°): The unit used to measure angles
60° Angle: An acute angle that is exactly one-sixth of a full rotation (360°)
- Draw a straight baseline from point A to point B
- Place protractor center exactly on point A
- Align the protractor's base line with ray AB
- Locate 60° on the inner scale of the protractor
- Make a small mark at the 60° point
- Remove the protractor and draw a ray from A through the mark
Start by drawing a horizontal line segment AB of any convenient length
Place the center of the protractor exactly on point A (the vertex)
Ensure the protractor's base line aligns perfectly with ray AB
Find the 60° mark on the inner scale and make a small dot
Draw a straight line from point A through the marked point
You have successfully drawn a 60° angle. This angle is perfect for constructing an equilateral triangle.
• Center Alignment: Protractor center must be on vertex A
• Baseline Alignment: Ray AB must align with protractor base line
• Scale Selection: Use inner scale for counterclockwise angles
• Precision: Make small, accurate marks when indicating degrees
135° Angle: An obtuse angle that is three-quarters of a right angle (90°) plus another right angle
- Draw a horizontal baseline from vertex O
- Position protractor with center at O and baseline aligned to 0°
- Since 135° is greater than 90°, use the inner scale
- Locate 135° on the protractor scale
- Mark point P at 135° and draw ray OP
Mark point O as the vertex of your angle
Draw a straight line from O extending to the right (this is the initial side)
Center the protractor on O with the baseline aligned to 0°
Find 135° on the inner scale of the protractor and mark point P
Draw ray from O through P to create the terminal side
Optionally, measure the angle again to confirm it's 135°
Your 135° angle can be used to create interesting geometric patterns and art.
• Obtuse Recognition: 135° is between 90° and 180°
• Scale Selection: Use the correct scale (inner or outer) depending on direction
• Precision: Make sure measurements are accurate to the nearest degree
• Verification: Always double-check important angle constructions
90° Right Angle: An angle that forms a perfect L-shape, exactly one-quarter of a full rotation
- Draw a horizontal line from point C
- Place protractor center at C with baseline aligned to 0°
- Mark point D at exactly 90° on the protractor scale
- Draw vertical line from C to D
- Verify with protractor if needed
Draw a horizontal line segment CE from left to right
Center protractor at point C with baseline CE aligned to 0°
Locate the 90° mark on the protractor and make a precise dot
Draw a line from C through the 90° mark to create the vertical side
Measure the angle again with protractor to confirm it's 90°
Label the angle as ∠ECF = 90°
You have created a perfect right angle that can be used to build squares and rectangles.
• Right Angle Identity: 90° is exactly one-fourth of 360°
• Verification: Always double-check right angles as they're fundamental
• Perpendicularity: The two sides are perpendicular to each other
• Accuracy: Right angles are crucial for geometric constructions
Angle Drawing Steps
Draw Baseline
Create the first ray of the angle
Position Protractor
Center on vertex, align with baseline
Locate Degree
Find target degree on scale
Mark & Connect
Mark point and draw second ray
• Acute angles: 0° < angle < 90°
• Right angle: exactly 90°
• Obtuse angles: 90° < angle < 180°
• Straight angle: exactly 180°
• Full rotation: exactly 360°