src/Maths/Geometry/Circle.php
public function getOrdinateByAbscissa($x)
    {
        $o = $this->getPointO();
        return (sqrt(pow($this->getRadius(), 2) - pow(($x - $o->getAbscissa()), 2)) + $o->getOrdinate());
    }
public function getOrdinateByAbscissa($x)
    {
        $o = $this->getPointO();
        return (sqrt(pow($this->getRadius(), 2) - pow(($x - $o->getAbscissa()), 2)) + $o->getOrdinate());
    }
Get the ordinate of a point of the circle by its abscissa

y = sqrt( r^2 - (x - Ox)^2 ) + Oy

@param   float   $x
@return  float