Shapes are everywhere — in toys, tiles, windows, and nature. In this chapter we learn to identify and describe 2D shapes (flat shapes), understand their properties (sides, corners), and explore simple patterns using shapes.
2D Shapes and Their Properties
| Shape | Sides | Corners |
|---|---|---|
| Triangle | 3 | 3 |
| Square | 4 (equal) | 4 |
| Rectangle | 4 | 4 |
| Circle | 0 (curved) | 0 |
| Pentagon | 5 | 5 |
| Hexagon | 6 | 6 |
- Key Terms
- Side: a straight line that forms the boundary of a shape
- Corner (vertex): the point where two sides meet
- Closed shape: a shape with no gaps or openings
Patterns with Shapes
A repeating pattern follows a rule. For example: circle, square, triangle, circle, square, triangle... the unit of the pattern is circle-square-triangle.
---
Example 1: Identifying shapes
A shape has 4 equal sides and 4 right-angle corners. What is it?
Answer: Square
Example 2: Counting sides and corners
How many sides and corners does a hexagon have?
Answer: A hexagon has 6 sides and 6 corners.
Example 3: Shape pattern
Look at the pattern: square, circle, square, circle, ___.
The pattern repeats every 2 shapes. The next shape is: square.
Example 4: Shapes in real life
Name a real-life object shaped like a rectangle.
Answer: A book, door, or window frame (many acceptable answers).
Example 5: Drawing and describing
Draw a triangle with 3 equal sides. What do we call it?
Answer: A triangle with all 3 equal sides is called an equilateral triangle.
---
- Key Ideas
- A circle has NO sides and NO corners — it is a curved shape.
- A square is a special rectangle where all 4 sides are equal.
- The number of sides and corners in a shape (polygon) are always equal.
Common mistakes
- Saying a circle has 1 side — it has no straight sides, only a curved boundary.
- Confusing a square and a rectangle — all squares are rectangles, but not all rectangles are squares.
Summary
2D shapes are flat. We identify them by counting sides and corners. Shapes follow patterns in art, nature, and design. The more you look, the more shapes you will spot!