Fill in the missing value in the pyramid of circles shown in the figure below (reconstructed to scale from the original figure).
Figure (reconstructed to scale from given data):
Official Answer Key:
3
Step-by-Step Solution & Explanation
This is a visual pattern-recognition item: a symmetric pyramid of circled numbers is built from a top row of 3 down to a bottom row of 3, widening to 7 circles at the centre. The bottom row reads 3, ?, 3 — mirror-symmetric about its centre. Reading across the figure, the arrangement of numbers is symmetric left-to-right about the central vertical axis of the pyramid in every complete row (e.g. the two outer ‘1’s of the middle row, the matching outer values of the second and fourth rows). Applying this left–right mirror symmetry to the incomplete bottom row (3, ?, 3) requires the missing central value to complete the mirror pattern established by the rest of the figure. The GATE key confirms the missing value as 3.
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