如图,在△ABC中,BD ,CE分别是∠ABC,∠ACB的平分线,AM⊥CE,AN⊥BD,若AB=8,BC=9,AC=7,求MN的长?拜托了
如图,在△ABC中,BD ,CE分别是∠ABC,∠ACB的平分线,AM⊥CE,AN⊥BD,若AB=8,BC=9,AC=7,求MN的长?拜托了
数学人气:179 ℃时间:2019-10-26 07:06:55
优质解答
延长AM、AN,与直线BC分别交于P、Q.AMC = PMC = 90 ACM = PCM CM = CM AMC PMC AM = PM CP = CA 同理可证:AN = QN BQ = AB (1)MN //PQ 即:MN//BC (2)MN = 1/2PQ =1/2 (AC AB-BC)=3
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