SOLUTION: I am making a round fairy princess skirt for my granddaughter. I have a solid circle cut out (ie, no seams). I need to put a hole in the center for her waist to fit into. The measu

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Question 42092: I am making a round fairy princess skirt for my granddaughter. I have a solid circle cut out (ie, no seams). I need to put a hole in the center for her waist to fit into. The measurement of her waist is 20". I can't remember how to find the radius of a circle so I can fold the fabric and cut out a hole that would have the circumference of 20".
Thank you in advance for your help. If you show me the equation I would really appreciate it. I used to love math but haven't used it like this for 40 years.
Best regards,
Tina

Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
If radius of a circle is 'r' then the circumference = 2%2A%28pi%29%2Ar.
Measurement of waist is 20" means the circumference is 20".
Thus, 2%2A%28pi%29%2Ar+=+20
or r+=+10%2F%28pi%29
or r = 3.183"

So the reqd. radius is 3.183 inches.