Medicine taken by a patient breaks down and eventually leaves the patient’s system. Suppose a dose of 60 milligrams (mg) of medi
cine is given and it breaks down such that 20% of the medicine becomes ineffective every hour. How much of the 60 mg dose is still active after 3 hours, after 4.25 hours, after hours?
c = circumference
pi = 3.14
r = radius = 9 inches
d = diameter
c=pi*d
The radius is half of the diameter, d = 2r. Then d = 2*9=18.
plug into equation. c= pi*d = 3.14*18
round accordingly and you may want to include that the measurement you end up with is in inches.