Step 1: Identify the number of sides in each shape:
- SQUARE has 4 sides, the second number 6 seems to be related to the properties of a square (4 sides + 2 diagonals).
- CUBE has 6 sides, matching the number 4 (which is also related to its faces in some interpretation).
- RECTANGLE has 4 sides, but 8 does not fit logically in the same way. The number 8 doesn’t correlate to its geometry.
- TRIANGLE has 3 sides, which similarly doesn’t correspond to 8 correctly either.
Step 2: By comparing all, RECTANGLE stands out, and its relation to 8 is an outlier.
Conclusion: The odd one out is RECTANGLE - 8 because the number of sides in the figure is more directly related to the second number in the other options.