9th Class Mental Ability Analytical Reasoning Analytical Reasoning

The chapter Analytical Reasoning is based upon the counting of various geometrical figures in a given complex figure.

EXAMPLE

1.         Count the number of triangles in the following figure. 

(a) 16                           (b) 22                                        (c) 28                                (d) 32

Explanation (c):

Let us label the components of given triangle as given below:

Number of triangles made up of one component (triangle) each =12.

There names are : 1,1, 3,...., 12.                            

Number of triangles made up of two components each = 8.                            

Similarly, number of triangles made up of 3 components each = 4.                                      

And number of triangles made up of 6 components each = 4.

Hence, number of all the triangles

= 12 + 8 + 4 + 4 = 28.

2.         In the following question, find the number of straight lines in the given figure.

(a) 18                                        (b) 20                            (c) 24                              (d) None of these                                    

Explanation (d)