搜搜做题作业网第2.3小题求解答,
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第2.3小题求解答,
2
PQ//BC,
AP:AB=AQ:AC
(AB-PB):AB=AQ:AC
(13-3x):13=2x:6
x=39/22s
3
设AP=Xcm时,S平行四边形PQCR=16cm²;
AB=BC=8,
PR//BC,AP:AB=PR:BC,AP=PR=X.
PB=BQ=AB-AP=8-AP=8-X.
SRT△ABC-SRT△APB-SRT△PBQ=S平行四边形PQCR
AB*BC/2-AP*PR/2-PB*BQ/2=16
8*8-X²-(8-X)²=32
64-X²-64+16X-X²=32
X²-8X+16=0
(X-4)²=0,
X=4(cm),
AP=X=4cm.
PQ//BC,
AP:AB=AQ:AC
(AB-PB):AB=AQ:AC
(13-3x):13=2x:6
x=39/22s
3
设AP=Xcm时,S平行四边形PQCR=16cm²;
AB=BC=8,
PR//BC,AP:AB=PR:BC,AP=PR=X.
PB=BQ=AB-AP=8-AP=8-X.
SRT△ABC-SRT△APB-SRT△PBQ=S平行四边形PQCR
AB*BC/2-AP*PR/2-PB*BQ/2=16
8*8-X²-(8-X)²=32
64-X²-64+16X-X²=32
X²-8X+16=0
(X-4)²=0,
X=4(cm),
AP=X=4cm.