Answer:
<h2>The radius is 4 units long.</h2>
Step-by-step explanation:
The given equation is

This equation belongs to a circle, which center is at (0.5, 3.5) and its radius is 4.
You can deduct its elements, becase this equation of the circle is explicit, which means the constant term represents the square power of the radius. Solving that, we have

Therefore, the radius is 4 units long.
What is the math problem?
If A=38x-x^2 then
dA/dx=38-2x
d2A/dx2=-2
Since the acceleration, d2A/dx2 is a constant negative, when velocity, dA/dx=0, it will be an absolute maximum for A(x)
dA/dx=0 only when 38=2x, x=19
A(19)=38(19)-19^2
A(19)=722-361
A(19)=361 ft^2
So the maximum possible area is 361 ft^2
(This will always be true as the maximum possible area enclosed by a given amount of material will always be a perfect square...)
First of all we need to realize that half of a yard is as much as 18 inches. If a diameter of the circle is 18 inches, then its radius is 18 ÷ 2 = 9 inches.