title: Check whether a line-segment intersects the perpendicular line draw from a particular point?
body: <p>As shown in this image:</p>
  
  <p><img src="https://i.stack.imgur.com/jte0V.png" alt="alt text"></p>
  
  <p>I have a set of line segments.  I want to check which line-segments intersect with the perpendicular line drawn from a given point (x0,y0).</p>
  
  <p>(E.g.: AB passes the check and BC does not.)</p>
  
  <p>The only information I've got is two points of the line-segment, (x1,y1), (x2,y2), and the target point (x0,y0).</p>
  
  <p>Is it possible to derive a simple formula using these three points?</p>
  
  <p>Thanks in advance.</p>
  
  <p>umanga</p>