40 is 1 tenth because 40 x 10 is 400
It would be $196/4months which should be $49 a a month for 4 months.
If the diameter is 12 inches, the radius is 6 inches, because the radius is half the diameter.
Given the formula
we have
When you fold the circle in half, the resulting figure has half the area.
So, you start with a circle with area
You fold it once and you have a semicircle with area
You fold it twice and you have a quarter circle with area
Not sure if im right but i think you just do 6x3 and theirs your answer 18.