Simone
∵AFEC是菱形∴FE∥AC，又E、F、B在同一直拿宏键线上∴B在FE上绝纯，BE∥AC∴∠EBC=∠BCA又ABCD是正方形，则∠BCA=∠EBC=45°∴∠ABF=∠EBC∠ABC=135°又AF=AC=√2AB,在△ABF中：AF/Sin∠ABF=AB/Sin∠AFB=2R∴Sin∠AFB=ABSin∠ABF/AF=ABSin∠135°/（√2AB）=1/2又∠ABF=135°Sin∠AFB=1/2得∠AFB=30°∴∠BAF=180°-∠ABF-∠AFB=180°-135°-30°=15°在正方形ABCD中，∠BAC=45°∠FAC=∠DAC-∠DAF=30°AFEC是菱形，则AE平分角∠FAC∴∠FAE=∠消巧CAE=15°=∠BAF即AE、AF三等分∠CAD
