How do i find the answer to 19?

Word Problem What is the prescribed dosage of a certain medicine for a 6-year-old child if the adult dosage of the medicine is 180 milligrams? The formula below is used to calculate the correct dosage for a child: a at12 A C = child's dosage in milligrams a = age of the child A = adult dosage in milligrams 17. What does variable "a" represent? (1) Type answer here in 18. What does variable "A" represent? Type answer here 19. Using the formula above, solve for C. Show your work. Type answer here