> even professional mathematicians find the answer strangely counter-intuitive Stereotyping, I doubt that. Engineers, sure, it's not intuitive that the length

> even professional mathematicians find the answer strangely counter-intuitive Stereotyping, I doubt that. Engineers, sure, it's not intuitive that the length increases by so little. Mathematicians: \pi(d + \Delta d) - \pi*d = \pi\Delta d. Sometimes there are benefits to staying abstract