Date: Feb 14, 2014 9:00 PM
Author: ken quirici
Subject: Euclid's Elements Book 1 Proposition 1 - something Euclid missed?

According to Wikipedia, Book 1 Proposition 1 (constructing equilateral triangle on given line segment)
is missing a premise - that if two different circles share a radius (that is, a line segment connecting
their centers is a radius for both circles).

Could somebody provide a proof of this premise?