Figure Classification – Aptitude (VITEEE)
Figure classification is a common type of question in aptitude tests.
You are presented with a set of figures (or a single figure) and asked to:
- Choose the figure that does not belong
- Group figures into categories
- Identify the common property among a set
The key to solving these questions quickly is to check for simple geometric properties that can be compared across all figures.
1. Simple Explanation
- Figures are 2‑D shapes drawn on a plane.
- Classification means grouping them according to a common attribute (e.g., number of sides, symmetry, angles, regularity, etc.).
- In aptitude tests, you usually have to pick the odd one out or pair figures that share the most similar property.
2. Key Points (Quick Checklist)
| Property | How to check | Typical classification |
|---|---|---|
| Number of sides | Count straight edges | Triangle, Quadrilateral, Pentagon, etc. |
| Types of angles | Look for right, acute, obtuse | Right‑angled triangle, acute triangle, obtuse triangle |
| Side equality | Are all sides equal? | Equilateral triangle, Regular hexagon |
| Vertex angles equality | Are all interior angles equal? | Regular polygons |
| Symmetry | Mirror axes, rotational symmetry | Axially symmetric, rotationally symmetric |
| Convex/Concave | Does any interior angle > 180°? | Convex, Concave |
| Presence of circles | Is the figure a circle or contains a circle? | Circle, Ellipse |
| Area/Perimeter similarity | Rough size comparison (often optional) | Similar shapes, same area |
| Orientation | Horizontal, vertical, diagonal | Right‑angle orientation |
| Vertices based on coordinate grid | Integer coordinates, lattice points | Lattice polygons |
Tip – In exam time, start with the easiest property: number of sides or symmetry. If that gives a clear odd one out, you’re done. If not, move to the next property.
3. Worked Example
Question
Four figures are shown below. Which figure does NOT belong?
A) Square
B) Rectangle
C) Rhombus
D) Equilateral triangle
(All figures are drawn with equal dimensions in the diagram.)
Step‑by‑Step Solution
-
Identify basic property
- Square: 4 equal sides, 4 right angles.
- Rectangle: 4 sides, opposite sides equal, 4 right angles.
- Rhombus: 4 equal sides, opposite angles equal, no right angles (unless it’s a square).
- Equilateral triangle: 3 equal sides, 3 equal angles (60° each).
-
Count number of sides
- Square, rectangle, rhombus → 4 sides.
- Equilateral triangle → 3 sides.
-
Conclusion
The figure that does not belong is D) Equilateral triangle because it has a different number of sides.
Answer: D
4. Quick Revision Summary
- Start with the simplest attribute (number of sides, presence/absence of right angles, symmetry).
- Use a checklist: sides → angles → side equality → angle equality → symmetry → convexity.
- Look for the odd one out: the figure that differs in the majority of the chosen attributes.
- Remember common categories:
- Triangles: Equilateral, Isosceles, Scalene, Right‑angled, Acute, Obtuse.
- Quadrilaterals: Square, Rectangle, Rhombus, Parallelogram, Trapezium, Kite.
- Regular polygons: All sides and angles equal.
- Irregular polygons: Any variation.
- Practice pattern recognition: The more you practice, the faster you become at spotting the key property.
Final Tip – In a multiple‑choice setting, the correct answer often appears as the only figure that breaks the most obvious pattern. Keep your eyes on the basics!