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This problem trains for: SAT-I, SAT-II, Math Kangaroo 5-6, Math Kangaroo 7-8, Math Kangaroo 9-10.

An equilateral triangle is folded across one if its midlines. What is the ratio between the overlapped area and the area of the figure thus resulted?

In the figure, the overlapped area is shaded. The figure resulted is a trapezoid.

figure

The trapezoid is formed of three triangles congruent to the overlapped area. Therefore,the ratio is 1:3.