Education Technology

Middle Grades Math: Exploring Areas of Irregular Polygons

by Texas Instruments


  • 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

About the Lesson

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.