Two Dimensional Shapes – Basic 1 Mathematics Lesson Note (Second Term)

Basic 2D shapes are the circle, square, triangle and rectangle. A circle is round with curved lines and no corners. A square has 4 equal sides and 4 corners. A triangle has 3 sides and 3 corners. A rectangle has 4 sides, two long and two short, and 4 corners.

Behavioural objectives

By the end of the lesson, students should be able to:

• name a circle, square, triangle and rectangle;
• count the sides and corners of each shape;
• tell which shapes have straight lines and which have curved lines;
• describe, match, find and draw the four shapes.

What are the basic 2D shapes?

Circle: ○

• Has curved lines
• Round shape
• No corners

Square: □

• Has 4 straight lines
• 4 equal sides
• 4 corners

Triangle: △

• Has 3 straight lines
• 3 sides
• 3 corners

Rectangle: ▭

• Has 4 straight lines
• 4 sides (2 long, 2 short)
• 4 corners

Evaluation

Exercise 14: Name these shapes

1. ○ = _____
2. □ = _____
3. △ = _____
4. ▭ = _____

Exercise 15: Count the sides

1. Triangle has _____ sides
2. Square has _____ sides
3. Rectangle has _____ sides
4. Circle has _____ sides

Exercise 16: Count the corners

1. Square has _____ corners
2. Triangle has _____ corners
3. Rectangle has _____ corners
4. Circle has _____ corners

Exercise 17: Shapes with straight lines

Circle the shapes with straight lines: ○ □ △ ▭

Exercise 18: Shapes with curved lines

Circle the shapes with curved lines: ○ □ △ ▭

Exercise 19: Describing shapes

Complete the descriptions:

1. A circle is _____ and has no corners.
2. A square has _____ equal sides.
3. A triangle has _____ sides and _____ corners.
4. A rectangle has _____ sides and _____ corners.

Exercise 20: Match shapes to descriptions

• Round with no corners → Circle
• 4 equal sides → Square
• 3 sides and 3 corners → Triangle
• 4 sides (2 long, 2 short) → Rectangle

Assignment

Exercise 21: Find shapes around you

1. Name something that is a circle: _____
2. Name something that is a square: _____
3. Name something that is a triangle: _____
4. Name something that is a rectangle: _____

Exercise 22: Draw these shapes

1. Draw a circle:
2. Draw a square:
3. Draw a triangle:
4. Draw a rectangle: