The figure below shows a circumscribed
trapezoid ABCD (AD // BC) with BC, CD, AD, and AB tangent to the
inscribed circle at points E, F, G, and H. DE and CG intersect at K. If
CE = 2 and DG = 5, find KF.
Geometry problem solving is one of the
most challenging skills for students to learn. When a problem
requires auxiliary construction, the difficulty of the problem
increases drastically, perhaps because deciding which
construction to make is an illstructured problem. By
“construction,” we mean adding geometric figures (points, lines,
planes) to a problem figure that wasn’t mentioned as "given."
