Apollonius was a man who wrote a book called Conics. There are 8 of these books. In theses books he brought to us words like ellipse, hyperbola, and parabola. Parabola is a plane cucrve generated by a point so moving that it's distance from a fixed point devided by it's distance from a fixed line is equal to 1. And this is what he explained. He also said that an ellipse was an elongated circle or a regular oval or in other words a closed plane curve generated by a point so moving that its distance from a fixed point devided by it's distance from a fixed line is a positive constant less than 1. He also explained that a hyperbola is a plane curve generated by a point so moving that it's distance from a fixed point devided by it's distance from a fixed line is a positive constant greater than 1.Thanks to him and his knowlege and understanding we know more about these subjects than before.