Final answer:
To represent the relationship between the number of short boards and 54 inches, we use the equation 3x + 12 = 54, solve for x, and find that each board is 14 inches long.
Step-by-step explanation:
The task is to write an inequality representing the relationship between the number of short boards and a total length of 54 inches. Given that adding 3 of these boards end to end along with a 12-inch ruler equals 54 inches, we can express this situation with the equation 3x + 12 = 54, where x represents the length of one board in inches.
To solve this, subtract 12 from both sides to isolate the term with x on one side resulting in 3x = 42, then divide by 3 to get x = 14. Therefore, the length of each individual board is 14 inches.