Answer: A
Step-by-step explanation: The question states that the change wasn't a positive one, it was a negative one as it states that the temperature changed an average of -2.250 Fahrenheit per hour. So, we multiply that by 3 to get -6.75. This is why A is correct.
Area=pi times radius^2 so
if area=4pi=pi times r^2
4 times pi=r^2 times pi
divide both sdies by pi
4=r^2
square root
2=radius since legnth cannot be negative
radius=1/2 diamters
2 radius=diameter
2(2)=diameter=4
diameter=4