How to Calculate the Diameter of a Circle

Step-by-Step Guide

1. 1

   Step 1: If you know the radius of the circle

   The radius is the distance from the center of the circle to its edge.
   
   For example, if the radius of the circle is 4 cm, then the diameter of the circle is 4 cm x 2, or 8 cm. , π is equal to approximately
   3.14 but you should use your calculator to get the most accurate results.
   
   For example, if the circumference of the circle is 10 cm, then the diameter is 10 cm/π, or
   3.18 cm. , This goes back to manipulating the formula for finding the area of a circle, A = πr2, to get the diameter.
   
   You can transform this into r = √(A/π) cm.
   
   For example, if the area of the circle is 25 cm2, divide that by π and find the square root.
   
   This equals cm
   2.82cm, so the diameter of the circle is
   2.82 x 2 =
   5.64cm.
2. 2

   Step 2: double it to get the diameter.

3. 3

   Step 3: If you know the circumference of the circle

4. 4

   Step 4: divide it by π to get the diameter.

5. 5

   Step 5: If you know the area of the circle

6. 6

   Step 6: divide the result by π and find its square root to get the radius; then multiply by 2 to get the diameter.

Detailed Guide

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