Hi All, I'm not a math guy so I am coming to you for help. I am trying to come up with an equation to graph any 180 degree curve that is comprised of: a 135 degree radius, and a 45 degree ellipse (135 + 45 = 180). The two curves being the same curvature (slope?) where they meet. The portion of the ellipse I want to use would be the part between line B (the vertical one) and line A (the red one), on the drawing below. The radius portion would start at A and go to the right. <click image to make it larger> Given: the length of the semi-major axis of the ellipse, the length of the semi-minor axis of the ellipse, and the radius. Use any example numbers you like (but remember the curvature (slope?) of the radius and the curvature (slope?) of the ellipse have to be the same where they meet, so I believe that means the value of the radius is dependent on the values of the ellipse). Please don't take this wrong, but I'm an older guy, and this isn't homework, so ideally I would like someone to solve it (if it is possible), and then briefly explain it to me. As opposed to someone leading me around to try to solve it for myself - which would be extremely painful for both of us! Thanks very much.