To answer this question, we need to transform all the values into one type of measure. In this case, we can work with inches. Then, we have:
Then, we have that in two feet we have 24 inches. Then, we have:
Juan's dog: 24 inches + 3 inches ---> 27 inches tall.
Peter's dog: 9 inches tall.
Now, how much taller is Juan's dog than Peter's dog is:
Therefore, Juan's dog is 3 times taller than Peter's dog.