correction Last section: "Since Wantzel's proof we know for sure that an arbitrary angle can't be trisected using a ruler and straightedge, but this doesn't stop people trying." Replace "ruler" with "compass" Reply
Last section: "Since Wantzel's proof we know for sure that an arbitrary angle can't be trisected using a ruler and straightedge, but this doesn't stop people trying." Replace "ruler" with "compass"