“…In general, the written data related to proving shows that geometric proving skills of prospective teachers are weak (Healy & Hoyles, 2000;Kahan, 1999;Senk, 1985), they have difficulties in proving (Chazan 1993a;Harel & Sowder 2007;Hart, 1994;Healy & Hoyles, 2000;Martin & Harel 1989;Riley, 2004;Senk, 1985), they have misconceptions like that only an example which shows accury of the statement or a numeric demonstration is e nough for proving (Goulding, Rowland, & Barber, 2002;Knuth, 2002;Ma, 1999;Martin & Harel, 1989;Morris, 2002;Simon & Blume, 1996) and they are not able to transfer their current knowledge into the process of proving.…”