geometria piana
https://picasaweb.google.com/marinofurlan2/Area_simmetria?authuser=0&feat=directlink
circonferenza e cerchio
cerchio1a.gif
cerchio1a
https://picasaweb.google.com/lh/photo/3uC3-U9O1J6AFxpQULWBgNMTjNZETYmyPJy0liipFm0?feat=directlink
cerchio2a.gif
cerchio2a
https://picasaweb.google.com/lh/photo/gZWuuL6BgqKDmet5oAJDBtMTjNZETYmyPJy0liipFm0?feat=directlink