FetishFuel said: Feet are, in general, about the length of the forearm, so it's actually proportional, check it yourself! Peer evaluation is the foundation of sound science :)
I did my measurements and, if my body is representative, her toes are too long, thus making the feet half-a-palm longer than the forearm.
Even if her feet are too long, that lamppost is equally far too short. Misaka isn't overly tall, so a grown-up man would be looking down at it. Although considering the bench as well, it makes me think the location is one of those miniature parks for children.