Making an angle with a protractor is a straightforward process involving drawing lines guided by the tool's markings.
To create an angle of a specific measurement using a protractor, follow these steps:
Preparing Your Drawing
- Start with a Baseline: Draw a straight line segment on your paper. This will form one side (or ray) of your angle.
- Mark the Vertex: Choose one endpoint of this line segment to be the vertex of your angle. Make a clear dot at this point.
Using the Protractor
- Position the Protractor: Place the protractor on your paper so that its center point (usually marked with a small hole or crosshairs) is exactly on the vertex dot you made.
- Align the Baseline: Rotate the protractor so that the baseline you drew lines up perfectly with the 0-degree line on the protractor's scale. You can choose to align it with either the 0-degree mark on the left or the one on the right.
- Locate the Desired Angle: Find the desired angle measurement on the protractor's scale. Important: Use the scale that starts at 0 degrees on the baseline you aligned. If you aligned with the right 0, use the outer scale (typically ascending from right to left). If you aligned with the left 0, use the inner scale (typically ascending from left to right).
- Make a Mark: Make a small pencil mark on your paper at the point on the protractor that corresponds to your desired angle measurement. This mark should be just outside the curved edge of the protractor.
Completing the Angle
- Connect the Vertex to the Mark: Remove the protractor. Using a ruler or the straight edge of the protractor, draw a straight line from the vertex dot to the mark you made on the paper. This line forms the second side (or ray) of your angle.
- Finalize: The two lines originating from the vertex now form the angle you intended to create. You can add an arc and the degree measurement between the lines to label the angle.
As shown in the reference from the video, drawing the line from the marked degree point to the vertex dot is the final step that defines the angle:
"...And draw a line from the 100 degree mark to the dot the vertex. That we drew. In. And we now have our 100 degree angle. Now for drawing the same angle measurement from the right side we use the same."
This highlights that once the desired angle is marked on the protractor's edge, connecting that mark back to the vertex completes the angle. The reference also notes that the same method applies whether you start aligning your baseline from the left or right side of the protractor, utilizing the corresponding 0-degree scale.
This process allows you to accurately construct angles of various degrees.
