Odd Shape Out

In Odd Shape Out questions you are given a set of shapes (usually five) and you must find the one that does not belong. The other shapes all share a common rule — one shape breaks it. This question type tests your ability to spot similarities and differences quickly.

CEM exams can use shapes that look unfamiliar or complex, but the underlying rules are always about the same set of properties. Let us work through them.

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How Odd Shape Out Works

You are shown five shapes labelled A to E. Four of them share one or more features in common. Your job is to identify the rule that connects the four and find the shape that breaks it.

Quick Example

Shape A	Shape B	Shape C	Shape D	Shape E
Large black circle	Large black square	Large black triangle	Small white circle	Large black pentagon

Rule: Four shapes are large and black. Shape D is small and white.

Answer: Shape D is the odd one out.

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Properties to Check

Work through these properties systematically every time:

1. Shape Type and Number of Sides

Check	Examples
Straight vs curved	Are most shapes straight-sided, with one curved?
Number of sides	Four shapes with 4 sides and one with 5 sides
Regular vs irregular	Four regular shapes and one irregular

2. Size

Shapes can be large, medium, or small. If four shapes are the same size and one is different, that is a strong clue.

3. Shading and Fill

Fill type	Description
Solid (black)	Completely filled in
Empty (white)	Just the outline
Grey	A mid-tone fill
Striped	Lines running across the shape
Dotted	Small dots filling the interior

4. Orientation and Rotation

Four arrows might point upward while one points to the left. Four triangles might sit flat on their base while one is upside down.

5. Internal Elements

Look for dots, lines, crosses, or small shapes inside the main shape. Check how many there are and where they are positioned.

6. Line Style

The border could be solid, dashed, thick, or thin. One shape might use a dashed outline while the rest are solid.

7. Symmetry

Four shapes might have a vertical line of symmetry while one does not.

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Worked Example 1 — Shading

Shape A	Shape B	Shape C	Shape D	Shape E
Striped circle	Striped triangle	Striped square	Solid black hexagon	Striped pentagon

Step 1: Check shading. Shapes A, B, C, and E are all striped. Shape D is solid black.

Answer: Shape D is the odd one out.

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Worked Example 2 — Number of Sides

Shape A	Shape B	Shape C	Shape D	Shape E
Triangle (3)	Pentagon (5)	Heptagon (7)	Square (4)	Nonagon (9)

Step 1: Count the sides: 3, 5, 7, 4, 9.