Question

How do I do #8? Pleas explain thank you

Answer 1

Basically what u want to do is take the 36 - 12 and hopefully u should get ur answer which would be 24 inches

Answer 2

12 inches to 36 inches....if it is increasing (going from a smaller number to a larger number), then it is a percent increase

increase = (new number - original number) / original number...* 100
               = (36 - 12) / 12.....* 100
               = 24/12 * 100
               = 2 * 100
               = 200% increase <==

now as far as a decrease (when it goes from a larger number to a smaller number) the formula is : 
decrease = (original number - new number) / original number..* 100