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I was wondering if anybody knew how to find the width of a circle in any given y position. For example, lets say you have a unit circle, the radius is 100 units tall. Now three fourths the way up the circle, 25 units above the center of the circle, there is a line parallel to the x axis that extends from one edge of the circle to the other. it looks a bit like this.

How big is that line, and what algorithm did you use to solve this?

I. C.
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    How is this a programming question? – Leeor Dec 09 '15 at 17:57
  • Questions seeking debugging help ("why isn't this code working?") must include the desired behavior, a specific problem or error and the *shortest code necessary* to reproduce it in the question itself. Questions without a clear problem statement are not useful to other readers. – PaulProgrammer Dec 09 '15 at 17:58
  • Read this lol https://www.khanacademy.org/math/geometry – Adam Buchanan Smith Dec 09 '15 at 18:03
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    I'm voting to close this question as off-topic because it's about basic math and OP didn't show any effort to solve the problem. –  Dec 09 '15 at 18:25
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    Scratch users are typically children who are just learning programming and have not had Geometry classes yet. – BoltBait Dec 09 '15 at 18:29
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    Paul. I spent two hrs. last night trying to find a solution – I. C. Dec 10 '15 at 07:56
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    First result on Google for this question with a great answer and its locked. – kagronick Mar 13 '21 at 05:07

1 Answers1

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First, label what you know:

Circle Labeled

Looks like a triangle to me.

Now, solve for X and double it:

x^2 + 25^2 = 100^2 (Pythagorean theorem)

x^2 = 9375 (Simplify)

x = 96.8 (Square root both sides, now we know x)

Length of chord: 193.6 (Length of chord is 2 times x)

Here is a site that can help you: http://www.mathopenref.com/chord.html

Since you tagged your question with Scratch, here is a function to help you:

Solution in scratch

BoltBait
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    I tried this, but I forgot to double it. – I. C. Dec 10 '15 at 06:49
  • @I.C. do you see the votes to close based on you not showing code and the question not being programming. If you had included a screenshot or a description of your attempt (not doubled), there'd be no vote down / vote to close. – boisvert Dec 15 '15 at 07:36