A decrease in moving from the bottom of Group 3 to the top of the group shows an increase in trend from top to bottom.
The atomic radius of elements increases from top to bottom and decreases from the bottom to the top.
The elements in group 3 are B, Al , Ga, In and Tl
Atomic radius is taken as half of the inter-nuclear distance between two covalently bonded atoms of non-metallic elements or half of the distance between two nuclei in the solid state of metals.
Downs a group from top to bottom, atomic radii increases progressively due to successive shells being added.
This compensates for the size reducing effect of the increased nuclear charge.
2 cm east is the answer because you go east 5.5 cm and then go back in a sense 3.5 so its basically 5.5-3.5 because its backwards while still facing eat