The Elegant Way to Find the Area of the Green Triangle

In this geometry puzzle, we are given a rectangle ABCD containing a green triangle EFC. The three corner triangles have areas of 4, 5, and 9 square units—and we aren't given a single side length of the rectangle! Can you determine the area of the green triangle? Watch as we turn this geometry problem into an elegant quadratic equation and solve it without ever finding the rectangle's dimensions. Try solving it on paper first, and share your method in the comments! #Geometry #MathPuzzle #Math #LogicBooster