Figure series: Reasoning Ability Notes for Andaman & Nicobar Islands PSC

📚 Reasoning Ability – Figure Series

(Andaman & Nicobar Islands PSC – Reasoning Ability – 2026)

Goal: Recognise the underlying rule that governs a sequence of shapes and predict the next figure.

1. Simple Explanation

A figure series question shows a chain of two‑ or three‑dimensional shapes.
Each figure in the chain is related to the previous one by a single or combination of the following operations:

Operation	What it looks like
Rotation	90°, 180°, 270°…
Reflection (Flip)	Horizontal, vertical, or diagonal mirror
Translation	Shift left/right/up/down
Scaling	Shrink or grow (size change)
Color change	One colour → another
Shape change	Triangle → square → circle etc.
Number of elements	1 → 2 → 3, or 3 → 2 → 1
Position change	Left → centre → right

The rule may involve one of these operations, or a combination (e.g., rotate 90° then colour change).
Your task:

Identify the operation(s).
Apply it to the last figure to obtain the missing figure.

2. Key Points to Remember

#	Key Point	Why it matters
1. Look for symmetry	Many series use mirror or rotational symmetry. Notice if the figure flips or turns around a centre.
2. Count the objects	Count shapes, corners, vertices, or dots. A common rule is “increase/decrease by 1 each step.”
3. Observe colours	A single colour change often signals a rule (e.g., “change to the next colour in the sequence”).
4. Note size changes	Size often scales down/up by a fixed factor (½, ⅔, 2×, etc.).
5. Pay attention to orientation	Rotating 90° clockwise each step is a common pattern.
6. Check position shifts	Moving left → centre → right, or up → down, is frequently used.
7. Look for a “hidden” element	Sometimes a new shape appears (e.g., a dot appears in the centre after a rotation).
8. Combine clues	The rule could involve two operations (e.g., rotate 90°, then change colour).
9. Test your hypothesis	Apply the rule to all figures except the missing one to confirm consistency.
10. Eliminate options quickly	If a choice violates any identified rule, discard it immediately.

3. Worked Example

Question:
Find the missing figure in the series below.
(Four figures are shown; the fourth is missing.)

[Fig 1]  ←  ▲ (triangle)  in **red**
[Fig 2]  ←  ▲ (triangle)  in **red**, rotated 90° clockwise
[Fig 3]  ←  ▲ (triangle)  in **blue**, rotated 180° clockwise
[Fig 4]  ←  ______

Answer Choices
A. ▲ (triangle) in blue, rotated 270° clockwise
B. ▲ (triangle) in red, rotated 270° clockwise
C. ▲ (triangle) in blue, rotated 0° (no rotation)
D. ▲ (triangle) in red, rotated 0° (no rotation)

Step‑by‑Step Solution

Step	Observation	Rule deduced
1	Colour change: red → red → blue. The colour changed only once (in Fig 3).	Colour changes once after the second rotation.
2	Rotation: 0° → 90° → 180°. Each step adds another 90° rotation.	Rotation increases by 90° each step.
3	Apply to Fig 4: Start at 0°, add 90° → 90°; add 90° → 180°; add 90° → 270°.	Rotation should be 270°.
4	Colour: After the second rotation (180°) colour switched to blue. The next rotation (270°) does not change colour again.	Colour remains blue.
5	Select answer: The figure that matches 270° rotation and blue colour is Option A.	✔️

Final Answer: Option A – ▲ (triangle) in blue, rotated 270° clockwise.

4. Quick Revision Summary

Topic	Quick Tips
Identify the rule	Count shapes, colours, rotations, translations, and sizes.
Check symmetry	Mirror/rotational patterns are common.
Track operations	Note if each step adds the same amount of rotation, translation, or size change.
Look for colour changes	Colour often changes after a set number of steps.
Combine clues	Two operations can coexist (e.g., rotate + colour).
Validate	Ensure the rule holds for all given figures before predicting the missing one.
Time‑saving	If a candidate answer violates any identified rule, discard it immediately.

Practice Tip:
Draw the given figures on paper, write down the operations you observe, and then apply the same operations to the last figure. This visual reinforcement helps solidify the pattern recognition process.

Good luck with your preparation! 🚀