中考几何动态真题

(1)

如图1,∵BA⊥AM,MN⊥AP,∴bam = anm = 90∴∠paq+∠man =∠man+∠amn = 90∞。

mn⊥ac,∴∠pqa=∠anm=90 ∴aq=mn,∴△aqp≌△mna∵an=pq

AM=AP,∴∠AMB =∠APM∠APM =∠BPC∠BPC+∠PBC = 90,∠AMB+∠abm = 90∞。=个人电脑

(2)

(1)方法一:如图1,∵BA⊥AM,MN⊥AP,∴ BAM = ANM = 90 ∴∠ PAQ+∠ MAN+。

mn⊥ac,∴∠pqa=∠anm=90 ∴aq=mn,∴△aqp≌△mna∵an=pq

AM=AP,∴∠AMB =∠APM∠APM =∠BPC∠BPC+∠PBC = 90,∠AMB+∠abm = 90∞。方法二:如图1,∵BA⊥AM,MN⊥AC,∴∠ BAM = ANM = 90 ∴∠ PAQ+∠ MAN = ∠ AMN = 90。∴∠APM =∠amp∠aqp+∠bam = 180,∴pq∨ma∴∠qpb =∠amp ∴.

PC=3,∴来自(1),PC=AN=3∴AP=NC=5.

AC=8,∴am = AP = 5∴AQ = Mn = = 4≈paq =∠amn∠ACB =∠anm = 90∴∠ABC =∞。那么CF=3k∴=,ne = K .设n为NTFE,CF为t,那么四边形ntfe为平行四边形ne = tf = k,∴CT = cf∴TF = 3k÷k = k÷ef ͸.∴tan∠NTC==2,∴CT=k=,∴k=,∴CK=2×=3,bk = BC∶CK = 3∶PKC+∶dkc。Tan∠ABC=,∴设GK=4n,那么BG=3n,GD=4n∴BK=5n=3,∴n=,∴BD=4n+3n=7n=∴AB==10.

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