Hello! Welcome to our new classroom.What's in the classroom? Look! A big blackboard, a teacher's desk, six pictures, many desks and chairs and a new computer in it.You can see eight new fans and four big lights.The wall is white and the floor is blue.The door is orange and the windows are green.My desk and my chair are near the window.I like my new classroom.

在△ABC中，∠A=$\frac{\mathrm{\pi }}{6}$，D是BC边上任意一点（D与B、C不重合），且丨$\overrightarrow{AB}$|²=${\left|\overrightarrow{AD}\right|}^2+\overrightarrow{BD}·\overrightarrow{DC}$，则∠B=____ ．

体重是衡量身体健康与否的重要指标，世界卫生组织给出了一些相关资料：

资料一：人体标准体重测算公式：

男性的标准体重（千克）=身高（厘米）-105，女性的标准体重（千克）=身高（厘米）-100

资料二：14岁-18岁青少年实际体重和标准体重的比值与营养状况的评价指标表

小明，男，今年15岁，在体检时，测得身高为165厘米，体重为70千克.