兄弟俩有一块平行四边形的土地，在四边形内有一口水井（如图），水井P是平行四边形ABCD内一点．兄弟俩要求平分这块土地，且都能方便地用水井浇地。弟弟说：“平行四边形的对角线把平行四边形分成两个全等的三角形．全等三角形的面积也相等，那么把一条对角线作出来一分为二不 The brothers had a parallelogram of land, with a well in the quadrilateral (pictured), and the well P was a point within the parallelogram ABCD. The brothers demanded that the land should be evenly divided, and that the land could be easily poured into the well. The younger brother said: "The diagonal of the parallelogram divides the parallelogram into two congruent triangles. The congruent triangles have the same area. Then divide one diagonal into two.