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Learning Objectives

By the end of this lesson, you will be able to:

Recognize and name common 3D solids (cube, cuboid, sphere, cylinder, cone, pyramid) (Objectives 100-103)
Identify properties of solids (faces, edges, vertices) (Objectives 104-106)
Recognize and name plane shapes (triangle, square, rectangle, circle, pentagon, hexagon) (Objectives 107-108)
Identify properties of plane shapes (sides, corners/vertices, lines of symmetry)

SEA Tip

Geometry questions appear in Section I and II of the SEA Math paper. Know your shapes and their properties! (SEA Framework Page 23-24)

Watch: Recognizing & Naming Solids

Start by watching this video to learn about 3D solids and their names. Take notes as you watch! 📝

Recognizing & Naming Solids – Mathematics Video Lesson

Quick Check

Did you understand the video? Review the notes below before continuing! ✅

3D Solids (Three-Dimensional Shapes)

3D solids have length, width AND height. They take up space! Let’s learn the common solids for SEA.

Cube

6 square faces
12 edges
8 vertices

Cuboid

6 rectangular faces
12 edges
8 vertices

Sphere

1 curved face
0 edges
0 vertices

Cylinder

3 faces (2 flat, 1 curved)
2 edges
0 vertices

Cone

2 faces (1 flat, 1 curved)
1 edge
1 vertex (apex)

Pyramid

5 faces (1 base, 4 triangular)
8 edges
5 vertices

Memory Trick

Cube: All sides equal (like dice)
Cuboid: Box shape (like a shoebox)
Sphere: Ball shape (like a football)
Cylinder: Can shape (like a soda can)
Cone: Ice cream cone shape
Pyramid: Egyptian pyramid shape

Watch: Properties of Solids & Plane Shapes

Now watch this video to learn about faces, edges, vertices and plane shape properties. Pay attention! 🎯

Properties of Solids & Plane Shapes – Mathematics Video Lesson

Properties of Solids

Every 3D solid has three important properties you need to know for SEA!

📋 Key Terms:

Definitions

Term	Definition	Example
Face	A flat or curved surface on a 3D shape	A cube has 6 flat faces
Edge	Where two faces meet (a line)	A cube has 12 edges
Vertex (Vertices)	A corner where edges meet	A cube has 8 vertices

📊 Properties Table:

Solid	Faces	Edges	Vertices
Cube	6	12	8
Cuboid	6	12	8
Sphere	1 (curved)	0	0
Cylinder	3 (2 flat, 1 curved)	2	0
Cone	2 (1 flat, 1 curved)	1	1
Pyramid	5	8	5

Plane Shapes (2D Shapes)

Plane shapes are flat (2D). They have length and width but NO height!

Triangle

3 sides
3 vertices
3 angles

Square

4 equal sides
4 vertices
4 right angles

Rectangle

4 sides (2 pairs equal)
4 vertices
4 right angles

Circle

1 curved side
0 vertices
360° around

Pentagon

5 sides
5 vertices
5 angles

Hexagon

6 sides
6 vertices
6 angles

Common Mistake

Don’t confuse 3D solids with 2D plane shapes! A cube is 3D, but a square is 2D. A sphere is 3D, but a circle is 2D!

Lesson Complete!

Great job finishing Lesson 2.1! You’re mastering geometry for the SEA exam! 🎉

Back to SEA Maths

🔷 Lesson 2.1: Geometry – Solids & Plane Shapes