The π symbol, which stands for pi, is a repeating decimal that has thousands of place values. For simplicity, use 3. 14 to represent pi. [2] X Research source Since you need to convert pi to its numerical form anyway, plug 3. 14 into the equation from the start. Write it as C = 2√3. 14 x A.
Let’s say the area of the circle is 500 cm2. Set up the equation as 2√3. 14 x 500.
If our equation was 2√3. 14 x 500, then 3. 14 times 500 is 1,570. This now makes the equation 2√1,570.
The square root of 1,570 is 39. 6.
Multiply 39. 6 by 2, which is 79. 2. This means that the circumference is 79. 2 cm, and you’ve solved the equation.
Again, use 3. 14 to represent pi. Remember—the radius spans from the center of a circle to the rim. [8] X Research source
Let’s say the area of the circle is 200 cm2. The formula would be 200 = 3. 14 x R2.
If you divide 200 by 3. 14, the result is 63. 7. This makes the new equation 63. 7 = R2.
The square root of 63. 7 is 7. 9. This makes the equation 7. 9 = R, meaning that the radius of the circle is 7. 9. This gives you all the information you need to find the circumference.
Using the first option, 7. 9 x 2 = 15. 8, the diameter of the circle. This diameter times 3. 14 is 49. 6. For the second option, set up the equation as 2 x 3. 14 x 7. 9. First, 2 x 3. 14 is 6. 28, and that multiplied by 7. 9 is 49. 6. Notice how both methods give you the same answer.
