title: Circle and Line segment intersection
body: <p><img src="https://i.stack.imgur.com/rR70d.png" alt="enter image description here"></p>
  
  <ul>
  <li>I have a line segment (begin x1,y1, end x2,y2 (D=5 lets say) ) and a
  circle (radius R, center x3,y3)</li>
  </ul>
  
  <p>How can I check that if my line segment intersects my circle?</p>