You can't directly convert inches to cover a round ball. You need to calculate the surface area of the ball to figure out how much material you need.

Here's how to do it:

1. Formula for Surface Area of a Sphere:

The formula for the surface area of a sphere is:

* Surface Area = 4 * π * r²

Where:

* π (pi) is approximately 3.14159

* r is the radius of the sphere (half the diameter)

2. Calculate the Radius:

* The diameter of your ball is 12 inches.

* The radius is half the diameter: 12 inches / 2 = 6 inches

3. Calculate the Surface Area:

* Surface Area = 4 * 3.14159 * 6²

* Surface Area ≈ 452.39 square inches

Therefore, you would need approximately 452.39 square inches of material to cover a 12-inch round ball.