(1)∵∠B=∠B，∴RT△BAC∽RT△BCD，∴AC∶BC=CD∶BD(2)∵∠B+∠BCD=∠BCD+∠ACD=90°，∴∠B=∠ACD，∵CE=1/3AC，BF=1/3BC，∴CE∶BF=AC：BC=CD∶BD∴△CDE∽△BDF∴∠BDF=∠CDE，∴∠EDF=∠CDE+∠DCF=∠BDF+∠DCF=∠BDC=90°
