Standard representation of basketball throwing

basketball throwing has approximately a shape of parabola. Hence, we can find variables a,b & c such that f(x)=ax^2+bx+c will represent a parabola that the ball's orbit pass through it. In this applet you can try to find variables that will match to the ball's orbit in the picture.
have you manage to find the appropriate variables a, b & c? If the answer is "Yes!"- what are they? If the answer is "No..."- take another try, with the applet "vertex representation of basketball throwing".