The document discusses the sum of the interior angles of a triangle. It describes an activity where students tear off the corners of paper triangles and glue them together to form a straight line, demonstrating that the sum is 180 degrees. The activity has students then measure the angles of paper triangles with protractors to find the sum, with the essential question being what is the sum of the interior angles of a triangle?

1. A Triangle’s AnglesWhat’s the sum?11/9/09

2. ReviewWarm upKeep glue sticks for later.

3. ReviewWhat do we use a protractor for?How do we use it?

4. ReviewComplementary angles?Supplementary angles?

5. ReviewComplete Complementary & Supplementary Angles WS

6. EQ:What is the sum of the interior angles of a triangle?

7. How many degrees are in the three angles of a triangle?180How can we know for sure?

8. How many degrees -straight angle?180What kind of angle can we make with the triangle corners?

9. Hand out triangles.Tear off cornersGlue triangle leftover into notebook.

10. Place angles into a straight angle and glue down. What kind of angle did we all make?

11. Hand out green cards and Triangle Pattern record sheet w/ protractors.Each pair will share a pack of triangles.

12. Measure the angles of one triangle together.What is the sum of the angles?

13. Carefully measure and record the angle measurement for each angle. Then find the sum.Use calculators.

14. What might account for differences in angle measurements?

15. EQ:What is the sum of the interior angles of a triangle?

16. Homework:Missing angles on “How did the judge find out about the rotten milk?”