Solution:
Construct segments KL,LM and MK. Next, construct the three altitudes of triangle KLM that meet in its orthocenter, O. Since KL connects the two midpoints of AB and BC we know that KL∥AB it is easy to see that MT∥KO∥LQ since those lines are perpendicular to a pair of parallel lines. Similarly, KT∥MO∥LS and KQ∥LO∥MS.
Note that triangle KLM divides the original triangle ABC into four congruent parts, all similar to the original triangle (and thus all acute), so the perpendiculars we dropped from K,L, and M are just altitudes of the smaller triangles. Since all the smaller triangles are acute, all the altitudes will meet inside the respective triangles.
Because of all the parallel lines, we know that OLSM,OMTK and OKQL are all parallelograms having diagonals ML,KM, and LK, respectively. The diagonal of a parallelogram divides it into two congruent triangles, so triangle LSM is congruent to triangle MOL, triangle MTK is congruent to triangle KOM, and triangle KQL is congruent to triangle LOK. If we consider the hexagon KQLSMT to be composed of triangle KLM and the three outer pieces, we can see that triangle KLM is composed of three smaller triangles that are congruent to the corresponding outer pieces, so the area of the hexagon is twice the area of triangle KLM.
But triangle KLM connects the midpoints of the edges of triangle ABC so each of its sides is half the length of the corresponding side of triangle ABC, so triangle KLM is similar to triangle ABC, but with 1/4 the area. We previously showed that the area of KQLSMT is twice the area of triangle KLM, so the area of the hexagon is 1/2 the area of triangle ABC.
