Reasoning about Rates: Overlapping Squares

This GeoGebra example demonstrates how to reason about rates of change using two overlapping squares. It visualizes how the area of overlap varies as one square moves or resizes, linking geometric intuition to the concept of instantaneous rate of change. Core mathematical concepts include area, rate of change, and geometric transformations such as reflection and intersection. The construction uses Polygon to define the squares, Mirror to create symmetric copies, Intersect to find overlapping vertices, and a slider (button1) to animate the motion. Suitable for high school or introductory college students exploring derivatives and dynamic geometry, this example serves as a hands-on tool for understanding how geometric quantities change over time.