问题 填空题

△ABC中,∠BAC:∠ACB:∠ABC=4:3:2,且△ABC≌△DEF,则∠DEF=______度.

答案

设∠BAC为4x,则∠ACB为3x,∠ABC为2x

∵∠BAC+∠ACB+∠ABC=180°

∴4x+3x+2x=180,

解得x=20

∴∠ABC=2x=40°

∵△ABC≌△DEF

∴∠DEF=∠ABC=40°.

故填40.

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