src/Maths/Geometry/Line.php
public function getAbscissaByOrdinate($y)
    {
        if ($this->isVertical()) {
            return $this->getPointA()->getAbscissa();
        }
        return (($y - $this->getYIntercept()) / $this->getSlope());
    }
public function getAbscissaByOrdinate($y)
    {
        if ($this->isVertical()) {
            return $this->getPointA()->getAbscissa();
        }
        return (($y - $this->getYIntercept()) / $this->getSlope());
    }
Get the abscissa of a point of the line by its ordinate

@param   float   $y
@return  float