A problem I can't figure out?

Question

Here is the question:

Chrysler has developed plans to scale down their Dodge Dakota pickup truck so that their 2005 model was 80.2% as big in all length dimensions as the 2004 model. What percentage of the previous amount of paint is needed for the new model? (The amount of paint required will be directly proportional to the surface area.)

Any help would be greatly appreciated.

Answer 1

Surface area goes as the square of linear size, if all dimensions scale equally.

Every side of the truck will be both 0.802 as wide, and 0.802 as high, so each side will take only
0.802^2 = 0.643204 = 64.3% as much paint