2D and 3D Shapes — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. A shape with 5 sides is called a pentagon.
The prefix "penta" means five, so any polygon with 5 straight sides is named a pentagon — like the shape of a home plate.
2. A rectangular prism has 8 vertices.
A rectangular prism has 4 corners on its top face and 4 corners on its bottom face, which gives it 8 vertices in total.
3. A pyramid with a square base has 5 vertices.
A square pyramid has 4 corner vertices around the square bottom plus 1 pointed vertex at the top, for 5 vertices in all.
4. A shape with 6 sides is called a hexagon.
"Hex" means six, so any polygon with 6 straight sides is a hexagon — you can see this shape in a honeycomb.
5. A cone has 1 vertex.
A cone tapers from its round base up to one single point on top, and that point is its only vertex.
6. A sphere has 0 faces, 0 edges, and 0 vertices.
A sphere is one perfectly smooth curved surface, so there are no flat faces, no straight edges, and no corner points — every count is 0.
7. An octagon has 8 vertices.
An octagon has 8 sides, and each place where two sides meet forms a corner — so there are 8 vertices too.
8. A triangular prism has 6 vertices.
A triangular prism has a triangle with 3 corners on each end, and 3 + 3 gives it 6 vertices in total.
9. A triangle has 3 fewer sides than a hexagon.
A triangle has 3 sides and a hexagon has 6 sides, so subtracting 6 − 3 shows the triangle has 3 fewer sides.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each 3D shape to its number of vertices.
cube
→ 8
0
cone
→ 1
5
sphere
→ 0
8
square pyramid
→ 5
1
A cube has 4 corners on top and 4 on bottom for 8 vertices, a cone has just 1 point on top, a sphere is fully curved with no corners, and a square pyramid has 4 base corners plus its top point for 5.