Two-Dimensional Diagrams – Rectangles, Squares & Circles 🟥🟦⚪

Two-dimensional diagrams represent two dimensions (length × width) or area.
These diagrams show comparisons more effectively than bar diagrams because area reflects magnitude.

Used extensively in:

• Business reports
• Geography
• Economics
• Market share studies

What Are Two-Dimensional Diagrams?

Definition:

Two-dimensional diagrams present data using geometrical shapes (rectangles, squares, circles) where area is proportional to the magnitude of the variable.

Why Use Area Diagrams?

✔ Useful for comparison of large values
✔ Visually appealing
✔ Shows proportion more accurately than bars
✔ Suitable for wide-range data

Types of Two-Dimensional Diagrams 🧩

1. Rectangular Diagrams (Area Diagrams)

Structure:

Area = Length × Breadth
One dimension is kept constant; the other varies according to data.

Example:

Sales of Two Stores:

If width is constant, height is proportional.

Store B rectangle will be double the area of A (80 vs 40).

Uses:

• Sales
• Production
• Income
• Expenditure

2. Square Diagrams

Used when comparing quantities using side length proportional to √value.

Formula:

If area ∝ value →
Side = √value

Example:

If values are:
A = 25 → side = 5
B = 100 → side = 10

Square for B will be 4 times larger in area.

Advantage:

Clear proportionality for large numbers.

3. Circular Diagrams (Pie Charts)

Each circle’s area represents the magnitude.

Also used for component parts (like pie charts).

Formula:

Radius ∝ √value
Area = πr²

Example:

Values:
A = 36
B = 144

Radius of B = 2 × radius of A
Area of B = 4 × area of A

When Used:

• Market share
• Budget allocation
• Population composition

ASCII Diagram — Types of Two-Dimensional Diagrams

Rectangles
↓
Squares
↓
Circles (Pie)

Advantages ✔️

• Better for comparing wide-ranging values
• More attractive than 1-D diagrams
• Provides a sense of proportion

Limitations ❌

• Harder to construct
• Area judgment difficult for common people
• Not suitable for small differences

Summary ✨

Two-dimensional diagrams use area to represent data.
Types include:

• Rectangular diagrams
• Square diagrams
• Circular diagrams

Useful when magnitude differences are large.

Quiz Time! 🎯