The average height, in inches, of girls who are 3 years old or younger can be approximated by the function f(x) = 18.6 + 4.78 In x, where x represents the age in months. Use the function to determine the average height of girls who are 22 months old. (Source: CDC} What is the average height of girls who are 22 months old? _ inches (Round to the nearest tenth as needed.)