Student understanding of angles is not assessed on the GED math test. But there are questions dealing with angles on the TABE 11, 12, 13, and 14.

This lesson is made up of a series of angle puzzles which help students notice and wonder about different angle relationships., in particular, (1) when two lines intersect to form four angles, the opposite angles are equal. and (2) alternate interior angles are equal

Students are given the opportunity to develop their observations into claims and then they are given virtual tools to test those claims.

In the end, students can apply what they’ve learned about angle relationships and to informally learn the Triangle Sum theorem: the sum of all angle measures in any triangle is `180` degrees.

Here is what the first few puzzles look like:

Once students work through the beginning puzzles, they are invited to make a claim.

Then there is an interactive screen for testing and revising their claim.

Students are then invited to investigate someone else’s claim.