5 1/2 by 4 3/4 by 1/4 scale it down by 1/10

(11/20 by 19/40 by 1/40) OR (0.55 by 0.475 by 0.025)

Step-by-step explanation:

To scale down a set of measurements, simply multiply the original measurement by the factors you're scaling it by. For example, take the first measurement of 5 1/2. To scale this down, I turned the value into an improper fraction (11/2) to make the multiplication process easier. Then, I multiplied 11/2 by the factor of 1/10.

After that, I got 11/20, which is the new first measurement.