A group of redneck engineers were surrounding a flagpole trying to determine it's height. Their calculators were busy with tangents, and cosines, and even some of teh older ones had their sliderules out. They just couldn't determine the exact height of that pole.
About that time, a young girl happened by and she asked them what they were doing. After hearing their problem, she loosened a nut at the base of the pole, pulled out the bolt, and the flagpole came crashing to the ground. She turned around and said, "now all you have to do is measure it."
The engineers looked at her with dismay. "We need to measure the height, not the length!"