Final answer:
The length of the average common goldfish can be found by dividing the length of a yellow-banded angelfish (12 inches) by 4.8, which yields a result of 2.5 inches.
Step-by-step explanation:
To find the length of the average common goldfish, we can write an equation based on the information provided. The average length of a yellow-banded angelfish is given as 12 inches, and this length is 4.8 times the length of an average common goldfish. Let's define the variable x to represent the length of the common goldfish.
An appropriate equation to find x would be:
4.8x = 12
To solve for x, we need to divide both sides of the equation by 4.8:
x = 12 / 4.8
x = 2.5
Therefore, the length of the average common goldfish is 2.5 inches.