Question

Which shape could be thought of as being created by stacking congruent polygons

Answer 1

When they talk about congruent polygons, they meant geometric figures that are all equal in shape and size.

It's angled, and the side length is equal too.

When you piled equal polygons, you'll end up with what we call prisms. It's the 3D form of a polygon.

If you stack squares, you'll have a cube.

If you stack octagons, you'll have an octagon prism.

Answer 2

A square and also it could be a rectangular prism.