设三角形ABC面积是60CM²,
D是BC上的点,BD=1/3BC,
E是AC的中点,AD,BE交于O,
连OC,设三角形BOD的面积是x,
三角形AOE的面积是y,
由条件:三角形DOC的面积是2x,
三角形COE的面积是y,
3x+y=60÷2=30(1)
x+2y=60×2/3=40(2)
x=4,y=18
S阴=x+y=22(cm²)
20平方厘米
两个小三角形的面积分别是5和15平方厘米
画个图啊
A triangle, total area 60 centimeter squared. The line segment from one vertex to the midpoint of its opposite side and the line segment from another vertex to a trisecting point on its opposite intersect at a point. Find the shadowed area.
参照图片 http://www.ies.co.jp/math/java/geo/rottrib/rottrib.html