So for this problem what I did was I divided 210 (the total number of calories) / 10 (calories from the fat). The total came out to be 21 but the answer is incorrect. How would I go about solving this problem?

For percentages, we divide the part by the whole. In this case, the part is the number of calories from fat and the whole is the total number of calories.

10 / 210 = 0.0476 = 4.76%

Then, we need to round to the nearest tenth.

The answer is 4.8%

Hope this helps!