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jmc

geometry senior

Problem

problem
If is a square, is the midpoint of , is the midpoint of , and intersect at , and and intersect at , then the area of quadrilateral is
Solution
First, we find out the coordinates of the vertices of quadrilateral , then use the Shoelace Theorem to solve for the area. Denote as . Then . Since I is the intersection between lines and , and since the equations of those lines are and , . Using the same method, the equation of line is , so . Using the Shoelace Theorem, the area of is .
Final answer
\frac{7}{15}