Alarge hamburger (e. g., whopper) sandwich contains 628 kcalories and 36 grams of fat. approximately what percentage of the total energy is contributed by fat?

To calculate the calories from fat the number of grams of fat should be multiplied with 9. There are 9 calories per one gram fat. So, in 36 grams there are 324 calories. The hamburger contains 628 calories, from which 324 are fat. 
The percentage of the total energy contributed by fat is: 51,5% ~ 52%.