已知:如图,△ABC中,AB="AC," D、E在BC边上,且AD=AE,求证:BD=C
已知:如图,△ABC中,AB="AC,"D、E在BC边上,且AD=AE,求证:BD=CE...
已知:如图,△ABC中,AB="AC," D、E在BC边上,且AD=AE,求证:BD=CE
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证明:作AF⊥BC于F, ∵ AB="AC," AF⊥BC于F, ∴ BF=CF ∵ AD="AE," AF⊥BC于F, ∴ DF=EF, ∴ BF-DF=CF-EF即 BD=CE |
先过A作AF⊥BC于F,而AB=AC,根据三角形三线合一定理可得BF=CF,同理可得DF=EF,再根据等式性质易证BD=CE. |
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