Proof Construction 3: Similar Triangles

  1. Construct the diagram as shown. When you drag the figure, the givens should remain true.
  2. Test whether the conclusion is true. Here, we are testing whether two triangles are similar. We know three similarity tests. Decide which one to use, and make the appropriate measurements.
  3. If the conclusion appears to be true, write a two-column proof on a separate sheet.
  4. If the conclusion is false, modify the problem slightly. (Recall the example on the handout.) Write a two-column proof of your modified statement.