Yes because it is a higher number. 8 is higher then 3
They are both variables. General dependent variables. Meaning each ones values change depending on the others.
perimiter means all the way around, and im assuming this is a 4-sided shape, so 5+5+4+4 = 18 ft.
C because a number cube has six sides and there are six residents. So you have chosen correctly by picking C. You can say you decided that due to the number of residents being the same number as sides on a number cube that it would make sense to roll a number cube to predict the randomly chosen resident.