You should be able to set up a proportion between the sides something like (18+x)/x=(56+21)/56
If there are 12 grams of protein in all, and 4 servings, in order to get the amount of grams per serving you must divide 12 by 4.
12 divided by 4 = 4.
Therefore, there are 4 grams per serving.
She used 1221 wrapping paper for 21 gifts, so to find the individual amount, you would do:
1221/21
She used about 58.143 ft² of wrapping paper for each gift.