Fitting a Parabola

Use the sliders to match the parabola to the curve of the St Louis arch.[br]Vertex form of the equation of a parabola: y=a(x-h)^2+k[br][br]Does the parabola fit the arch perfectly? [br]What does this mean?[br][br]What is the vertex of the parabola?

Information: Fitting a Parabola