Classification

Classification means to assort the items of a given group on the basis of certain common qualities (characteristics) they possess and then spot the stranger (odd man) out.  We are required to select the figure which differs from all other figures in the given set.

Bases of Classification

The figures may broadly be classified on the following bases:

  1. SFR (Same figure rotates)

The four similar figures are actually the rotated forms of the same figure.  For example, in the figures below, it is only the rotation of the same figure in four figures while one of them is a different figure.

Example:

Solution: 3

  1. Number of lines or components

The figures may be classified on the basis of the number of lines or the number of components.  For example, all figures (except the odd man out) may be made of the same number of components; they all may be made of only even number of (or odd number of) lines or the sum (or difference) of the number of lines may be a fixed number etc. 

Example:

Solution: 5; all others are divided in six segments.

  1. Origin of Lines

Apart from the number of lines, the origin of lines is also an important consideration for some of the figures. Some figures are made of several components, an important component of which could be a line. The point from where it starts is an important factor to consider and it may be the basis on which a figure may be differentiated from the remaining four.

Example:

Solution: 5; all figures are made of two circles of different sizes, each circle having a line within it.  One of these lines is vertical and the other horizontal.  But in (5), both the lines are horizontal.

 

  1. Comparative positions of the elements

A figure consists of several components. Now it may be that in the figures all the components may have a definite position in relation to each other and this could be the basis on which any four figures could be said to be similar and the fifth could be said to be different.

Example:

Solution: 4; in each figure there are two identical shapes in rotated form.

  1. Other considerations

i. Interior-exterior consideration:

When a figure is made of more than one elements/components, it is naturally likely that some of the elements may lie within (interior) some other elements while some others may lie outside (exterior) the other elements. 

Example:

Solution: 5; All other figures exhibit non-parallelism except figure 5.

SYNTHESIS OF FIGURES

          In a given group of figures, each figure consists of several components and these components, their number, their positioning; their shape and size etc are formed according to a definite rule.  If we are able to spot the logic that is the basis of the synthesis of figures we may be able to detect the figure.

          It may be noted that we have already seen cases where the figures were created and classified on the basis of comparative shapes, sizes and positions of components or on the basis of number or origin of lines etc.  Even after these considerations have been made, it does not remain very easy to detect the logic or the algorithm behind the making of the figures.  However, with a little bit of foresight and experience, such problems can easily be tackled as the following examples suggest.