I will answer yours , will you answer mine
3 rows x 5 chocolates= 15 pieces per layer
15 pieces x 5 layers= 75 chocolates
"Enlargement" here implies that the two pentagons are similar. Because of similarity, the following equation of ratios must be true: 7/15 = x/7. Then 15x=49, and x = 49/15 = 3.27 cm, approximately.
Rounded to the nearest tenth, that comes to 3.3 cm.