question_answer

How many triangles are there in the following figure?

A) 16                                

B) 20

C) 12                                

D) 22

Correct Answer: B

Solution :

The figure in the question may be labelled as shown below. There are nine triangles in the upper half of the figure \[ABFE=\Delta AEI,\,\,\Delta AIG,\,\,\Delta AEG,\,\,\Delta GEO,\,\,\Delta GBJ,\,\,\Delta BFJ,\]\[\Delta GBF,\,\,\Delta GOF\,and\,\Delta GEF.\] Similarly, there are nine triangles in the lower half figure, i.e. EFCD. There are two more triangles\[\Delta EGH\]and\[\Delta FGH\] Hence, there are a total of 20 triangles.