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## Celebrate a Dog's Birthday Seven Times Each Year?

On the one hand, a dog is as old as the number of years it has lived. Yet, humans want to translate this age into human years.

There is no consensus as to the best conversion formula (or rules of thumb). Some suggested options are:

• Multiply the dog's age by 7
• Add 4 to the dog's age and then multiply by 4
• For the first two years, multiply by 10.5...then add 4 for every year after that
• A one-year-old dog is between about 10 and 15 years, the second year is equivalent to about another 3 to 8 years, and each subsequent year equates to 4 or 5 human years
Task 1: If a dog is 12 years old, how old is the dog according to each of these formulas?

Task 2: Represent the different formulas on a single graph (dog's age vs. human's age). Is there a single point where all agree? Also, which seems the most realistic? Explain.

Task 3: The oldest recorded age for a dog is 27 years. How old would this be in human years using each of the formulas?

If you are curious, a common formula for cats is their year one equates to 15 human years, year two equates to 10 more human years, and four human years for each cat year thereafter.

Task 4: The oldest recorded age for a cat is 34 years. How old would this be in human years?

And, for the horse lovers, a common formula for horses is that their year one equates to 6 human years, year two is equates to 5 more human years, year three equates to four more human years, year four equates to three more human years, and the 2.5 human years for each horse year thereafter.

Task 5: The oldest recorded age for a horse is 62 years. How old would this be in human years?