How to Calculate Landscape Blocks Per Radius
- 1). Decide what size landscaping blocks you will be using. They come in many sizes, from 5 inches to 24 inches long. This, along with the radius of circle you are trying to create, will be the largest determining factor for how many blocks you will need.
- 2). Determine the radius of the circle of blocks. Stand in the center of the circle, and fasten the end of your tape measure to an object on the ground. Extend the tape measure to the farthest point that you will need enclosed by the circle of landscaping blocks. Read the measurement on the tape measure; this is the radius of the circle.
- 3). Plug the value for your radius into the equation for the perimeter of the circle. The perimeter is the length of the outer edge of a circle, and is calculated using this formula:
Perimeter = 2 x pi x radius.
For example, if your radius is 20 feet, then:
Perimeter = 2 x 3.14 x 20 feet = 125.7 feet - 4). Divide the length of your perimeter by the length of the type of landscaping block you will be using. If you are using 10 inch blocks, which are 10/12 or 0.83 of a foot, then you will need:
125.7 / 0.83 = 152 blocks to form the perimeter of your circle.
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