@Robert Gentel,
Your inaccuracy by category:
Parallelogram 12.0 6.7 23.0
Midpoint 2.8 3.2 5.8
Bisect angle 3.2 2.9 1.2
Triangle center 4.7 9.7 5.2
Circle center 3.6 8.1 9.2
Right angle 2.1 0.8 3.7
Convergence 10.3 5.8 8.2
Average error: 6.30 (lower is better)
I'm horrible at the parallelograms as well. I can find a right angle like nobody's business, though!