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Printsmc
geometry senior
Problem
Let be a regular hexagon with side length . Denote by , , and the midpoints of sides , , and , respectively. What is the area of the convex hexagon whose interior is the intersection of the interiors of and ?
(A)
(B)
(C)
(D)
Solution
The desired area (hexagon ) consists of an equilateral triangle () and three right triangles ( and ). Notice that (not shown) and are parallel. divides transversals and into a ratio (This can be shown by similar triangles.). Thus, it must also divide transversal and transversal into a ratio. By symmetry, the same applies for and as well as and In we see that and Our desired area becomes
Final answer
C