are you asking how many values of x there are? if so, i'm pretty sure the answer is 3.
18
12 + 6 = 18
There Are 12 In One Year.
The ratio A/r² would represent

which is the circumference of a circle divided by its diameter.
You can see this because the area of a circle is

r² and if you divided that by the radius squared, you are given pi which is the circumference of a circle divided by its diameter.