Help i dont know what to do

Can some one me with these questions

Which of the following is an example of a rational number? a. π b. √ 9 c. √ 8 d. 3.8362319

The average daily maximum temperature for laura’s hometown can be modeled by the function f(x)=4.5sin(πx/6)+11.8 , where f(x) is the temperature in °c and x is the month. x = 0 corresponds to january.what is the average daily maximum temperature in may? round to the nearest tenth of a degree if needed.use 3.14 for π .