Question 939097
It is not right. You need to figure out what portion (fraction) of the 86 calories comes from fat.
It has to be less than 100%, because 100% is all of it.
If a certain percentage of the calories in some food is calories from fat,
it is not going to be more that 100% of the total.
Only football players give more than 100% of all they have.
 
Besides learning what percentages mean (and how to calculate them),
you have to take into account that a gram of fat provides 9 Calories
(or 8.8 Calories if you want to be more precise).
So, {{{0.4g}}} fat provides {{{0.4*(9Cal)=3.6Cal}}} .
That, as a fraction of the total energy in a glass of milk is
{{{3.6Cal/"86 Cal"=0.042=4.2/100=4.2%}}}
If you drink enough skin milk to consume 100 Calories,
about 4.2 Cal will be from fat.
That is 4.2 in 100, 4.2 per hundred, or 4.2 percent.
To calculate percentages, you calculate the ratio as a decimal, and then multiply times 100 to get the denominator of the fraction with 100 at the bottom.
The ratio you calculate is calories from fat, divided by total calories.
For percentages, you compare quantities measured in the same units.
So, 3.2% interest earned on a deposit of 100 dollars in 3.2 dollars, not 3.2 cents, or 3.2 rupees.
Likewise the percentage of calories from fat is calculated comparing the calories from fat (not the grams of fat) to the total calories.
 
NOTE: The "calories" that nutritionists and food labels talk about are big Calories,
what physics teachers call kilocalories.