Fractions that are equivalent to 4/12

At the beginning of the day, stock xyz opened at $6.12. at the end of the day, it closed at $6.88. what is the rate of change of stock xyz? a. 1.17% b. 11.0% c. 12.4% d. 81.5%

This is about circle theorems. someone asap : (

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).