I have the direct length between the start and end of a chord, and I have the included angle. How can I find the radius of the circle the arc is on?

Thanks

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- Jul 17th 2009, 02:03 PMtherealdrag0Circle From Included Angle and Chord Length
I have the direct length between the start and end of a chord, and I have the included angle. How can I find the radius of the circle the arc is on?

Thanks - Jul 17th 2009, 02:09 PMskeeter
- Jul 17th 2009, 02:25 PMtherealdrag0
Hm. I've looked at the page on Wikipedia: c^2 = a^2 + b^2 - 2*a*b*cos(y)

(because a=b) -> c^2 = 2a^2 - 2*a^2*cos(y)

but...I only have y (the angle) and c (the chord length), so I'm not sure what to do from here. - Jul 17th 2009, 02:29 PMskeeter
- Jul 17th 2009, 02:38 PMtherealdrag0
Ah; good move.

Thank you for the help. - Jul 17th 2009, 02:50 PMSoroban
Hello, therealdrag0!

Quote:

I have the length of a chord, and I have the included angle.

How can I find the radius of the circle?

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