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：
Is Working from Home as a Blogger a Good Fit?　 Why You Should Handwrite Your Blog Post First　 The Good Old Days – 5 Ways To Use Nostalgia Marketing In Ecommer　 7 Top Tools to Build Your Blog and Brand Like A Pro　 Top Reasons to Start a Blog During Lockdown　 3 Tips for Handling a National Crisis – From a Blogging Perspect　 6 Best WordPress Plugins for eLearning & Tutorial Websites　 A Successful Marketing Chain Examined　 4 Productivity Tips While You Work from Home During The Lockdown　 How Does an SSL Work on Your Blog?