Faces, Edges, and Vertices of 3D Shapes

🎯 What Will We Learn Today?

Flat shapes (2D) are just the beginning! Today we'll explore 3D shapes and learn about their faces, edges, and vertices.

📚 2D vs. 3D

2D shapes are flat: they have length and width only (like a drawing on paper)

3D shapes are solid: they have length, width, AND height (like a real box or ball)

📐 Three Important Parts of 3D Shapes

Faces

A face is a flat surface of a 3D shape. Think of the sides of a box — each side is a face.

Edges

An edge is where two faces meet. It's the "seam" or line between faces.

Vertices (singular: Vertex)

A vertex is a corner where edges meet. It's a pointy tip!

📊 Let's Count!

Cube (like a dice 🎲)

Faces: 6 (all squares)

Edges: 12

Vertices: 8

Rectangular Prism (like a shoebox 📦)

Faces: 6 (all rectangles)

Edges: 12

Vertices: 8

Triangular Pyramid (like a tent ⛺)

Faces: 4 (all triangles)

Edges: 6

Vertices: 4

🎮 Count the Parts!

Activity: Find a box (cereal box, shoebox). Touch and count:

How many faces? (the flat sides)

How many edges? (the lines where faces meet)

How many vertices? (the corners)

💡 Euler's Formula

For many 3D shapes: Faces + Vertices − Edges = 2

Check with a cube: 6 + 8 − 12 = 2 ✓

📝 Practice Problems

How many faces does a cube have?

How many edges does a rectangular prism have?

What is a vertex?

Find a cylinder. Does it have edges? Vertices?

Use Euler's formula: if a shape has 5 faces and 6 vertices, how many edges?

🎮 Play a Game!

Learn about 3D thinking with Tortuga Racing — race and learn geometry!