Constant Cross‑Sectional Area of a Prism

① This example constructs a prism by translating a polygon along a vector and demonstrates that any cross‑section perpendicular to the translation direction has a constant area. ② The core mathematics involve prism geometry, vector translation, area calculation of planar shapes, continuity principles, and the centroid properties of polygons. ③ The construction uses GeoGebra commands such as Vector, Sequence, Polygon, Centroid, and Translate, together with objects like Translate, Sides, F, B, and lists/polygons (list1, poly1, list2, poly2, etc.) to create the dynamic model. ④ It is intended for high‑school or early university students studying geometry and vectors, providing a visual tool for exploring solid geometry, transformations, and area invariance.