side BC = side FC and side BE = size EF, thus triangle BCE and FCE triangle are similar per SSS similarity theorem. So, the angle BEC and the angle FEC are the same, thus 90 degrees. So proved.
月光與狼==That characters' meaning are moonlight and the wolf being in Cantonese and Mandarin versions. Yip
... could they have got to ? How could you be so unkind ---so cruel--- don 't be cruel please.Could you please(....) ?