Steiner's solution.
Construction of Double elements (Xr and Xs): [url]http://www.geogebratube.org/material/show/id/35593[/url] ___________ Castillon's Problem (2 of 2) Solution 1: [url]http://www.geogebratube.org/material/show/id/30757[/url] [b]Solution 2: →Projection and Double Elements[/b] This is Problem #29 in Heinrich Dorrie's [i]100 Great Problems of Elementary Mathematics.[/i] More: [url]http://www.geogebratube.org/collection/show/id/2735[/url]