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共高三角形的性质:共高三角形的面积比等于对应底边的比.题目:如图1,S△ABD=12BD·h,S△ADC=12DC·h,从而S△ABD S△ADC=12BD·h12DC·h=BD DC.特别地,当AD为△ABC中线时,S△ABD=S△ADC.在相似三角形的学习中,此性质常与相似三角形面积比等于相似比的平方这一性质综合使用,现举两例说明.例1如图2,△ABC与△DEC重叠的情形,其中E在BC上,AC交DE于F点,且AB//DE.若△ABC与△DEC的面积相等,
Total high triangular nature: the total area of the triangle is equal to the ratio of the corresponding bottom edge. Title: As shown in Figure 1, S △ ABD = 12BD · h, S △ ADC = 12DC · h, which S △ ABD S △ ADC = 12BD • h12DC • h = BD DC. In particular, SΔABD = SΔADC when AD is the ABC ABC line. In similar learning of triangles, this property is often compared to the fact that the area ratio of similar triangles is equal to the square of the similarity ratio Example 1 As shown in Figure 2, △ ABC and △ DEC overlap case, where E in BC, AC AC DE in the F point, and AB // DE. If △ ABC and △ DEC Area is equal,