The cat should receive 1/5 of the can of food at each meal.
Step-by-step explanation:
Given that a cat is to receive 90 kcal of a canned food at each meal, and the food has a caloric density of 450 kcal per can, to determine what fraction of a can it should receive at each meal, the following calculation must be performed:
1 / (450/90) = X
1/5 = X
Thus, the cat should receive 1/5 of the can of food at each meal.