Simple angle question

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.

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

Pls never taught i’m really confused and i rlly need