Answer:
C. 
Step-by-step explanation:
= Diameter of a red blood cell = 
= Diameter of a whooping cough virus = 
Ratio of the diameter of the red blood cell to the diameter of the whooping cough virus

The required ratio is
.
Answer:
x=4.2. If you divide 12.6 by 3, you get 4.2
The answer would be 353.6
6 to the third power (or 6 times 6 times 6) would come out to be 216.
You'd then add 216 and 5 to get 221.
The next step would be to add 8 to 1/5 and get 1.6.
The final step would be to multiply 1.6 and 221 which would give you 353.6.