Lill's Circle
A historical geometric approach to solving quadratics, seen at Pat Bellew's great math history blog, http://pballew.blogspot.com/2014/05/more-geometric-solutions-to-quadratics.html
Thomas Carlyle gave a method of finding a circle to solve the quadratic . Eduard Lill discovered this and extended it to all polynomials. Read more at Wikipedia: http://en.wikipedia.org/wiki/Lill%27s_method