The answer is C- Berthas cake weighs 463 grams more than Jessups cake
The formula for calculating length is:

We can also write

or

Why it does not matter?
Let's assume we have 2 numbers, a and b.
When we perform a subtraction:

, we get another number

When we perform another subtraction:

, we get a number

When we raise

or

to the power of 2, the result is the same,

.
Step-by-step explanation:
a. 246,913,578
2+22+222+2,222+22,222+222,222+2,222,222+22,222,222+222,222,222
b. 0.3+0.33+0.333+0.3333+0.33333+0.333333+0.3333333+0.33333333+0.333333333 =2.962962963