Let's solve this step by step. We need to count the
faces,
edges, and
vertices for each 3D shape shown in the worksheet.
---
Definitions:
-
Face: A flat surface of a 3D shape.
-
Edge: A line segment where two faces meet.
-
Vertex (plural: vertices): A corner point where edges meet.
---
We'll go through each shape:
---
1) Triangular Prism
This is a prism with two triangular bases and three rectangular sides.
-
Faces: 2 triangles + 3 rectangles =
5 faces
-
Edges: Each triangle has 3 edges, but shared edges are counted once. Total: 9 edges
- 3 edges on top triangle, 3 on bottom, and 3 vertical edges connecting them →
9 edges
-
Vertices: 3 vertices on top triangle, 3 on bottom →
6 vertices
✔ Faces: 5, Edges: 9, Vertices: 6
---
2) Cube
A cube has 6 square faces.
-
Faces: 6 (top, bottom, front, back, left, right)
-
Edges: Each face has 4 edges, but each edge is shared by 2 faces → 6 × 4 ÷ 2 =
12 edges
-
Vertices: 8 corners
✔ Faces: 6, Edges: 12, Vertices: 8
---
3) Square Pyramid
A pyramid with a square base and 4 triangular faces meeting at a single apex.
-
Faces: 1 square base + 4 triangles =
5 faces
-
Edges: 4 edges on the base, and 4 edges from base to apex →
8 edges
-
Vertices: 4 base vertices + 1 apex =
5 vertices
✔ Faces: 5, Edges: 8, Vertices: 5
---
4) Hexagonal Prism
A prism with two hexagonal bases and 6 rectangular sides.
-
Faces: 2 hexagons + 6 rectangles =
8 faces
-
Edges: Each hexagon has 6 edges → 6 × 2 = 12; plus 6 vertical edges connecting the bases → total
18 edges
-
Vertices: 6 vertices per base → 6 × 2 =
12 vertices
✔ Faces: 8, Edges: 18, Vertices: 12
---
5) Rectangular Prism (Cuboid)
Same as a cube, but with rectangular faces.
-
Faces: 6 (all rectangles)
-
Edges: 12 (same as cube)
-
Vertices: 8
✔ Faces: 6, Edges: 12, Vertices: 8
---
6) Octahedron (Regular Octahedron)
This is a Platonic solid with 8 triangular faces.
It looks like two square pyramids glued together at their bases.
-
Faces: 8 equilateral triangles →
8 faces
-
Edges: Each triangle has 3 edges, but shared → 8 × 3 ÷ 2 =
12 edges
-
Vertices: 6 vertices (4 around the "equator", 1 top, 1 bottom)
✔ Faces: 8, Edges: 12, Vertices: 6
---
7) Pentagonal Pyramid
A pyramid with a pentagon base and 5 triangular faces.
-
Faces: 1 pentagon base + 5 triangles =
6 faces
-
Edges: 5 edges on base, 5 edges from base to apex →
10 edges
-
Vertices: 5 base vertices + 1 apex =
6 vertices
✔ Faces: 6, Edges: 10, Vertices: 6
---
✔ Final Answers Table:
| Shape | Faces | Edges | Vertices |
|------|-------|--------|----------|
| 1) Triangular Prism | 5 | 9 | 6 |
| 2) Cube | 6 | 12 | 8 |
| 3) Square Pyramid | 5 | 8 | 5 |
| 4) Hexagonal Prism | 8 | 18 | 12 |
| 5) Rectangular Prism | 6 | 12 | 8 |
| 6) Octahedron | 8 | 12 | 6 |
| 7) Pentagonal Pyramid | 6 | 10 | 6 |
---
You can now fill these values into the table on the worksheet.
Let me know if you'd like a visual explanation or help understanding any shape!
Parent Tip: Review the logic above to help your child master the concept of vertices edges and faces worksheet.