Final answer:
The blue whale is 28 yards long.
Step-by-step explanation:
To find out how long the blue whale is in yards, we need to use the conversion factor that there are 3 feet in 1 yard.
So, if the blue whale measures 84 feet long, we can use the conversion to find its length in yards:
84 feet × (1 yard/3 feet) = 28 yards
Therefore, the blue whale is 28 yards long.