Main problem

You are going to consider how the warm-up problem was created. You will need to create a similar problem with a different set of four straight lines.

  • How can you guarantee that your four lines will intersect to form a triangle where each point on the triangle has negative coordinates?
  • How can you ensure that just one triangle is created with these conditions?
  • How many approaches can you find to create a similar problem?
  • Which of your approaches to this problem is the most effective?

Once you have completed this problem you may like to consider the questions below to extend your thinking:

What conditions are there for four straight lines to enclose a square which has only negative coordinates for any point on that square?

How do these conditions vary if we wish to enclose other quadrilaterals?

You might like to try a graphical approach to this problem, perhaps using Desmos.