How to extend a line in java?

Question

Java

There is an object on the field, Circle with constant coordinates. When the user clicks on the screen, a line goes from the X and Y Circle and connects the clicked point to the center of the circle, there are many such lines. The problem lies in the fact that we need to extend the line and take it off the user's screen. And most importantly, the lengths of all these lines that go beyond the screen must be equal. This is where the whole problem lies. I don't know how to describe this, please help.

public boolean onTouchEvent(MotionEvent event) {

        int eventAction = event.getAction();

        if (eventAction == MotionEvent.ACTION_MOVE) {
            EndLx = 0;
            EndLx = 0;
            EndLx += (EndLx - PlayerX) ; 
            EndLy += (EndLy - PlayerY) ;
        }