The can of tomatoes is three times as tall but one-third as wide as the can of tuna. What is true about the areas of their labels?

Area of the label is calculated as diameter*PI*height

So if height of tomato can is 3 times the can of tuna: hTOM=3*hTUNA

Diameter of a tomato can is three times smaller so: dTOM=dTUNA:3

so Area of a tomato can label = A = (dTUNA:3) * PI*3*hTUNA

A=dTUNA*PI*hTUNA

and the area of a tuna can label=

A=dTUNA*PI*hTUNA

So, the label areas are the same.