In the previous lesson students explored the areas of triangles constructed between two parallel lines. In this lesson they apply this concept to solve a problem involving the areas of irregularly shaped quadrilaterals. After working the problem on their own, students share their solution methods with the class.

• Part 1: Linking Yesterday’s Lesson to Today’s Topic [Begin: 00:27]
• Part 2: Posing the Problem [Begin: 01:26]
• Part 3: Working on the Problem [Begin: 04:05]
• Part 4: Students Presenting Solutions [Begin: 19:20]
• Part 5: Reviewing Students’ Methods and Posing Another Problem [Begin: 22:31]
• Part 6: Summarizing the Results [Begin: 46:37]
• Lesson Table: The lesson table contains a detailed summary of the lesson's mathematical content.