Instead of simply telling students the formulas for memorization, this lesson guides students to consider the meaning of the formulas. It also creatively targets the misconception that the height of a figure is an simply the outside edge. This lesson focused on the area of parallelograms, triangles, and trapezoids, with special attention to a triangle as a trapezoid with a top base of zero.
This is one of 12 lessons in my "In and Out" unit that targets area and volume for 7th graders in the advanced track. The goal of the unit is to build understanding of why the formulas for area and volume work, such that if students forget the formulas, they can cognitively reconstruct them on their own.