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Trisecting an angle (Posted on 2008-08-24) Difficulty: 2 of 5
Trisecting an angle, using only compass and straight edge, was one of the great classical problems of antiquity.

Modern mathematics has proved it impossible, but here is a simple and ingenious mathematical cardboard device that trisects accurately:


If you place it properly, so the edge AB passes through the vertex of the given angle, one side of the angle passes through point C, and the other side tangents the arc MN (arc of the circumference centered at E and radius ED), the lines traced from the vertex through the points D and E trisect exactly the angle.

Prove it.

The device is perfectly drawn to scale, so you can get any information you need about lengths, parallelism, intersections etc...

See The Solution Submitted by pcbouhid    
Rating: 3.0000 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts re: ------------------ | Comment 5 of 8 |
(In reply to ------------------ by pcbouhid)

Would it not be possible to design the mathematical cardboard device with a using only a straight edge and compass?  If so, then doing so, in part, would be one of the solutions to trisecting an angle and that classical problem of antiquity.


  Posted by Dej Mar on 2008-09-01 06:51:53
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