数学题：如图，平行四边形ABCD面积是72平方厘米，E是AD靠近D点的三等分点。BD与CE相交于点F，则图中阴影部分面积是多少平方厘米？

数学题解答：这题用比例做的。

BF：FD=△BEC：△CED=3：1（三角形同底，所以BF秘FD之比等于面积之比）

阴影面积=72×1/2×1/3×3/4=9（由开心糊涂老师解答）

推荐阅读：
Are You Taking Advantage Of These Free WordPress Marketing Plugi　 What Content Marketers Can Learn from Game of Thrones　 All You Need To Know About How Small Business Should Handle Soci　 Should You Add Live Chat to Your Blog?　 Food Blogger Accuses Fast Food Giant Of Stealing His Recipe　 Back To School 2016: How To Rock (And Profit) With Sales And Mar　 The Five Fundamentals to Creating a Powerhouse Blog　 Blog On The Go With These Mobile Apps　 Here’s Why Your Content is Struggling　 Cloud Hosting vs. Traditional Hosting: Why Hosting Your Blog in