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5 votes

How can I build a protractor without a protractor?

In mweiss' method, the outer angles ∠AOC and ∠DOB are shy of 1° by slightly more than 0.0001°, and the inner angle ∠COD exceeds 1° by slightly more than 0.0002°. On a (huge!) one meter diameter ...
  • 3,041
1 vote

How can I build a protractor without a protractor?

Use a sine bar and some gauge blocks to machine a line in a the protractor. Repeat many times.
  • 111
13 votes

How can I build a protractor without a protractor?

Step 1: Find a machinable material that is reasonably incompressible. Step 2. Find a string material that is reasonably non-stretchy. Step 3: Make a cylinder out of the machinable material (perhaps ...
  • 3,041
17 votes

How can I build a protractor without a protractor?

As Will Orrick says in the comments under user20315's answer, it is possible, with straightedge and compass, to construct a regular 120-gon, and therefore it is possible to mark off every 3 degrees on ...
  • 16.5k
3 votes

How can I build a protractor without a protractor?

In terms of doing it on paper, it is impossible to trisect (or quintisect) angles with a conventional compass and straight edge. And 180 = 2 * 2 * 3 * 3 * 5. Of course you could be an anti-...

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