Instructional Video
Khan Academy

Khan Academy: Area of Composite Shapes

6th - 7th
Models how to break an irregular polygon into smaller composite shapes, calculate the area for each of those, then add all the amounts together to get the total area. [5:15]
Instructional Video
Khan Academy

Khan Academy: Decomposing Shapes to Find Area: Add

2nd - 3rd Standards
Demonstrates how to break an irregular shape into three rectangles, find the individual areas, and then add them together. [3:36]