梯形ABCD中,AD平行于BC,AB垂直于BC,AD=3,BC=5,将腰DC以D为中心逆时针旋转90°至DE,连接AE,则三角形的面积是（）.图自己画,）Akangaroorunssofastthatitcancatchupwithatrain.(同一句）答得好追加分!Akan

　　梯形ABCD中,AD平行于BC,AB垂直于BC,AD=3,BC=5,将腰DC以D为中心逆时针旋转90°至DE,连接AE,则三角形的面积是（）.图自己画,）

　　Akangaroorunssofastthatitcancatchupwithatrain.(同一句）答得好追加分!

　　Akangarooruns__________tocatchupwithatrain.