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Printsmc
geometry senior
Problem
The midpoints of the sides of a regular hexagon are joined to form a smaller hexagon. What fraction of the area of is enclosed by the smaller hexagon? 
(A)
(B)
(C)
(D)
Solution
is copied six times to form the hexagon, so if we find the ratio of the area of the kite inside to the the area of itself, it will be the same ratio. Let so that the area of the triangle is . Notice that is made up of a kite and two triangles. The two hypotenuses of these two triangles form , so the hypotenuse of each triangle must be . Thus, the legs of each triangle are and , and the area of two of these triangles is . Subtracting the area of the two triangles from the area of the equilateral triangle, we find that the area of the kite is . Thus, the ratio of areas is , which is option .
Final answer
D