Consider 10 lines drawn at a tangent to an ellipse. The lines break up the plane into several regions, some bounded (i.e., enclosed) and others unbounded. How many unbounded regions are there?

• If there are 10 tangent lines, then there are 20 unbounded regions.
  It is not very difficult to visualize that each tangent line drawn creates two unbounded regions.
  
  So, 10 lines means, 10*2 = 20 Unbounded regions.
• 12 years agoHelpfull: Yes(1) No(0)