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Folding a third is not nearly as impressive as angle trisection, which is impossible with a straight ruler and compass, but possible using origami. http://en.w
by murbard2 12y ago
Folding a third is not nearly as impressive as angle trisection, which is impossible with a straight ruler and compass, but possible using origami.
http://en.wikipedia.org/wiki/Angle_trisection#Using_origami http://en.wikipedia.org/wiki/Angle_trisection#Using_origami
- cbd1984 12y ago> angle trisection, which is impossible with a straight ruler and compass To be clearer: It is impossible to come up with a general algorithm to exactly trisect an arbitrary angle using only a straightedge (not a ruler) and a compass in a finite number of steps. And the straightedge isn't a ruler because it can't be used to measure distances. Neither can the compass. This is an axiom system, and therefore the rules are absolute. http://en.wikipedia.org/wiki/Compass-and-straightedge_construction http://en.wikipedia.org/wiki/Compass-and-straightedge_constr...
- murbard2 12y agoYes, I meant straight edge, sorry I had an ESL moment.
- pbhjpbhj 12y agoYou're not wrong per se - a ruler usually has graduations but _could_ just be a straight-edge. However, as the GP says, "ruler" implies a straight-edged measuring stick (aka "measure" [n]). Ruler derives, I gather, from Latin regula which just means a straight stick or bar and in turn derives from terms referring to keeping straight (literally or figuratively). tl;dr measuring stick ⊂ ruler.
- murbard2 12y agoMy native tongue is French, where it is "règle et compas", I translated règle tu ruler, but added straight in front vaguely remembering that the English expression had the word "straight" in it.
- Sniffnoy 12y agoNote in particular that it is possible to trisect an angle with a ruler and compass: https://en.wikipedia.org/wiki/Angle_trisection#With_a_marked_ruler https://en.wikipedia.org/wiki/Angle_trisection#With_a_marked...