Explore different ways to find areas of irregular polygons using the three basic shapes of rectangles, parallelograms, and triangles.

• Students will recognize that the area of an irregular shape is found as the sum of the areas of smaller, familiar polygons.
• Students will find the area of irregularly shaped polygons.
• Students will decompose irregular shapes into triangles, rectangles, and parallelograms in order to determine the area of real-world objects.

• polygon
• rectangle
• parallelogram
• triangle
• irregular polygon
• area
• area as a covering

This lesson involves using rectangles, parallelograms, and triangles to “fill in” the area of an irregularly shaped polygon. As a result students will: visualize the concept that irregular areas can be found by determining the sum of smaller, more familiar polygons.