四边行abcd是梯形,ae与梯形的腰cd平行.三角形bef比三角形adf的面积多5平方厘米,be/ec=3/2.求梯形abcd的面积.
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![四边行abcd是梯形,ae与梯形的腰cd平行.三角形bef比三角形adf的面积多5平方厘米,be/ec=3/2.求梯形abcd的面积.](/uploads/image/z/10201961-65-1.jpg?t=%E5%9B%9B%E8%BE%B9%E8%A1%8Cabcd%E6%98%AF%E6%A2%AF%E5%BD%A2%2Cae%E4%B8%8E%E6%A2%AF%E5%BD%A2%E7%9A%84%E8%85%B0cd%E5%B9%B3%E8%A1%8C.%E4%B8%89%E8%A7%92%E5%BD%A2bef%E6%AF%94%E4%B8%89%E8%A7%92%E5%BD%A2adf%E7%9A%84%E9%9D%A2%E7%A7%AF%E5%A4%9A5%E5%B9%B3%E6%96%B9%E5%8E%98%E7%B1%B3%2Cbe%2Fec%3D3%2F2.%E6%B1%82%E6%A2%AF%E5%BD%A2abcd%E7%9A%84%E9%9D%A2%E7%A7%AF.)
四边行abcd是梯形,ae与梯形的腰cd平行.三角形bef比三角形adf的面积多5平方厘米,be/ec=3/2.求梯形abcd的面积.
四边行abcd是梯形,ae与梯形的腰cd平行.三角形bef比三角形adf的面积多5平方厘米,be/ec=3/2.求梯形abcd的面积.
四边行abcd是梯形,ae与梯形的腰cd平行.三角形bef比三角形adf的面积多5平方厘米,be/ec=3/2.求梯形abcd的面积.
ae//dc, ad=ec.
be/ec=3/2, be=3ec/2=3ad/2, bc=5ad/2
三角形afd相似三角形efb. hf/gf=ad/be=2/3, gf=3hf/2, hg=5hf/2
S(bef)-S(adf)=5,
be*gf-ad*hf=5*2
(3ad/2)*(3hf/2)-ad*hf=10, ad*hf=8.
S(abcd)=(ad+bc)*hg/2
=(ad+5ad/2)*(5hf/2)/2
=35ad*hf/8
=35*8/8
=35
ae//dc, ad=ec.
be/ec=3/2, be=3ec/2=3ad/2, bc=5ad/2
三角形afd相似三角形efb. hf/gf=ad/be=2/3, gf=3hf/2, hg=5hf/2
S(bef)-S(adf)=5,
be*gf-ad*hf=5*2
(3ad/2)*(3hf/2)-ad*hf=10, ad*hf=8.
S(ab...
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ae//dc, ad=ec.
be/ec=3/2, be=3ec/2=3ad/2, bc=5ad/2
三角形afd相似三角形efb. hf/gf=ad/be=2/3, gf=3hf/2, hg=5hf/2
S(bef)-S(adf)=5,
be*gf-ad*hf=5*2
(3ad/2)*(3hf/2)-ad*hf=10, ad*hf=8.
S(abcd)=(ad+bc)*hg/2
=(ad+5ad/2)*(5hf/2)/2
=35ad*hf/8
=35*8/8
=35
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