Answer:
12cm
Step-by-step explanation:
The formula for Area is A = pi multiplied by (radius squared)
So, invert the formula to find the radius, which is half of the diameter.
Radius squared = area divided by pi
radius squared = 111.6/3.1
radius squared = 36
then, find the square root of 36, which is the radius.
radius = 6
so the diameter is radius x 2
so 6 x 2 = diameter
12 = diameter
then keep the units, so diameter = 12cm.
I hope that helps!!