This video provides highlights from three fourth-grade lessons designed to support students as they discover formulas for the area of parallelograms, triangles, and trapezoids. Students share different strategies and engage in classroom discussions, developing the concept of equivalent-area transformation and recognizing the efficiency of transforming the shape into rectangles or squares.

A document outlining the background and research on the content and standards, unit/lesson goals, and unit/lesson plan accompanies the video.