在三角形abc中,角ACB=90,cd垂直ab于d,ae是角cab的平分线,且交cd于e,cb于f

问题描述:

在三角形abc中,角ACB=90,cd垂直ab于d,ae是角cab的平分线,且交cd于e,cb于f
求证af比ae=cb比cd.求图与答,

做FM⊥AB,∠ACF=90°即FC⊥AC∵AF平分∠BAC,∴∠BAF=∠CAF,FM=CF即∠DAE=∠CAF ∵CD⊥AB∴∠ADE=∠ACF=∠ACB=90°∴△ADE∽△ACE∴∠AED=∠CFA=∠CFE∵∠AED=∠CEF∴∠CFE=∠CEF∴CE=CF=FM=CE∴FM∥CD(FM⊥AB,C...