Two blondes are hired by the Parks Department, given a big tape measure and told to measure the height of a number of trees in the park.
As the two keep trying unsuccessfully to throw the tape to the top of the tree, a huge muscle-bound weightlifter type comes along and asks what they’re doing. When they tell him, he wraps his giant arms around the tree, pulls it out of the ground, lays it down, measures it for them, and walks away.
One blond looks at the other and says “What a dope! We needed to measure the HEIGHT, not the length!”