Ethan will use 49 fl oz of orange juice when he uses 28 fl oz of sparkling water.
Ethan will have a total of 77 fl oz of punch.
Based on the given table, Ethan uses a ratio of 7 fl oz of orange juice to 4 fl oz of sparkling water. This means that for every 7 fl oz of orange juice, he uses 4 fl oz of sparkling water.
If Ethan uses 28 fl oz of sparkling water, we can determine the amount of orange juice he will use by setting up a proportion:
7/4 = x/28
Solving for x, we get:
x = (7/4) * 28
x = 49 fl oz
Therefore, Ethan will use 49 fl oz of orange juice when he uses 28 fl oz of sparkling water.
The total amount of punch can be calculated by adding the amount of orange juice and sparkling water:
Total punch = Orange juice + Sparkling water
Total punch = 49 fl oz + 28 fl oz
Total punch = 77 fl oz
Therefore, Ethan will have a total of 77 fl oz of punch.