As shown in the figure, triangle ABC is divided into triangle BDE and quadrilateral ACDE by line segment de. question: what is the area of triangle BDE that is the area of quadrilateral ACDE?
According to the graph, we can see that: the height on the bottom BD of △ BDE: the height on △ abcbc = 2: (2 + 6) = 1:4, & nbsp; & nbsp; & nbsp; s △ BDE: s △ ABC = (12 × 3 × 1): (12 & nbsp; × 7 × 4) = 3:28; therefore, the area of triangle BDE is the area of quadrilateral ACDE: 3: (28-3) 3:25 = 325