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Using A ProtractorUsing A Compass

Edited by Mike, Deniseke, Adelaide, Krystle and 4 others

Constructing accurate polygons is very significant in geometry and easy to do. If you have ever wondered about how to construct regular polygons from a circle, you’re reading the right article.

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Method 1 of 2: Using A Protractor

  1. Draw a Circle Step 6.jpg
    1
    Draw a circle to the desired amount of circle size. Use your compass to do this.
    • There should be a mid-point. If there is, lightly draw a straight line using a ruler across the circle by using the mid-point.
      Step_1 1.png
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  2. 2
    Divide the circle. Since a circle has 360 degrees, divide 360 degrees to the amount of vertices you have. For instance, use a dodecagon. This shape has 12 vertices, so 360 degrees divided by 12 comes out to be 30 degrees.
  3. Step_3.png
    3
    Mark a point for every divided amount (the dodecagon’s divided amount equals to 30 degrees as shown in the example before) with a protractor and pencil. Make sure you start at the line you have drawn.
  4. Step_5.png
    4
    Join the lines together for every mark you did (there should be 12 marks for a dodecagon because it has 12 vertices). Don’t overlap the lines.
    • If your points are outside of the circle, then simply mark another point onto the circle’s line for each point that is on the outside. Then, you can join them.
  5. 5
    Check to see if the sides are the same in length and width. If they are, you can rub out the outside circle.
  6. Step_7.png
    6
    Finished.

Method 2 of 2: Using A Compass

  1. Draw a Hexagon Step 2 Version 2.jpg
    1
    Draw a circle to the desired amount of circle size. Use your compass to do so.
  2. Draw a Hexagon Step 3 Version 2.jpg
    2
    Start from any point on the circle and mark an arc or line. Don't change the radius of your compass.
  3. Center
    3
    Mark another arc or line on the circle's line. Continue the process until the arc or line touches the first point. This will make a hexagon (6 arcs/lines) and only works for a dodecagon, triangle and a hexagon.
    • Make sure your compass doesn't move!
    • To make a dodecagon, measure the radius of the circle and half it on your compass and mark lines. It should mark 12 lines.
    • To make a triangle, measure the radius of the circle and double it on your compass and mark lines. It should mark 3 lines.
  4. Draw a Hexagon Step 7 Version 2.jpg
    4
    Join the lines/arcs accurately using a ruler.
    • Check to see if the sides are identical in length and width.
    • If they are, then you're finished. Rub the guidelines.
      Draw a Hexagon Step 8 Version 2.jpg
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Tips

  • If you want, you could draw the circle and mark the points lightly.
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Warnings

  • This works for a heptagon or with a divided angle amount with decimals, but it may not be that accurate. Guess the decimal position on the protractor.

Things You’ll Need

  • Protractor
  • Paper
  • Pencil
  • Eraser
  • Compass

Related wikiHows

How to
Draw a Polygon

How to
Draw a Hexagon


Article Info

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Categories: Featured Articles | Geometry

Recent edits by: Uraretard11, BR, Maluniu

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