Answer:

PRISM

Explanation:

Each figure is a prism with a regular polygon as base. The bottom most figure has 16-gon base, so it has 48 edges (16 from the top face, 16 from the bottom face, and 16 from the sides). Similarly, the one above it has 18-gon base. The ones shown in the image in the OP have 13-gon and 19-gon bases. It is natural to assume this is the top view, so these are the top two figures in the stack (the others are hidden under them). Counting the edges so far, we have (16+18+13+19)×3 = 198 edges. The remaining number of edges is 225 - 198 = 27, which means the middle figure is a prism with a nonagon (9-gon) base. Now, using A1Z26, we read from bottom to top: 16, 18, 9, 19, 13 -> PRISM.

As a check, there are totally 16+18+9+13+19 = 75 squares on the sides, and the remaining 10 polygons all form identical pairs (the tops and bottoms of the prisms).

Answer:

PRISM

Explanation:

Each figure is a prism with a regular polygon as base. The bottom most figure has 16-gon base, so it has 48 edges (16 from the top face, 16 from the bottom face, and 16 from the sides). Similarly, the one above it has 18-gon base. The ones shown in the image in the OP have 13-gon and 19-gon bases. It is natural to assume this is the top view, so these are the top two figures in the stack (the others are hidden under them). Counting the edges so far, we have (16+18+13+19)×3 = 198 edges. The remaining number of edges is 225 - 198 = 27. Also, we already have 16+18+13+19 = 66 squares and 8 other regular polygons that form identical pairs, so we need 75-6 = 9 more squares and 10-8 = 2 other polygons that form an identical pair. The only way to do this is to have a middle prism with nonagon (9-gon) base. Now, using A1Z26, reading from bottom to top, we have 16, 18, 9, 19, 13 -> PRISM.