Word problem F(x) log

Question

the percentage of adult height attained by girls who are x years old can be modeled by the given function where x represents the girls age (from 5 to 15) and f(x) represents the percentage of her adult height. Use the formula to determine approximately what percent of her adult height a girl has attained at the age of 5.

 

f(x)=62+35 log(x-4)

 

A 5 year old girl attained approximately %? of her adult height.

round to the nearest tenth as needed.  

Answer 1

f(x) = 62 + 35 log(x-4)

 

where x is a child's age and f(x) is the percentage of adult height attained at age x.  For a 5 year old girl, x = 5:

 

f(x) = 62 + 35 log(x-4)

 

f(5) = 62 + 35 log(5-4)

 

f(5) = 62 + 35 log(1)

 

Now any number raised to the zero power equals one; e.g, 10⁰ = 1.  So log(1)= log(10⁰) = 0.  Remember, the log returns the exponent of 10 needed to get the number in parentheses:

 

f(5) = 62 + 35*0

 

f(5) = 62%