it is 12 degrees colder in the mountains than in the valley. The temperature on the mountain is x. The temperature in the valley is y

The ratio of surface area to volume is the amount of surface area per unit volume of a thing. This is an important value in various topics. In chemistry, this is an important value for chemical reactions. It can show reactivity of a solid material. Also, it has found some importance in biology because it shows how the cells are affected by the environment where that cell is found.