Logic behind degree-rad convertion

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5 comments, last by MajinMusashi 19 years, 4 months ago
I know that to convert from degrees to rads I must do: => radValue = (degreeValue * 2 * pi) / 360.0f; But I don't know why! Could someone give me a simple answer (if there is one)?
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d / 360 will give a value between 0 (no rotation) and 1 (full rotation)

then multiplying that by 2pi to get rads because 2pi in rads is a full rotation

(2pi is a full rotation because the diamiter of a unit sphere is 2 and the cercumfrence is pi * diamiter)
180deg/pi rad = 1

x rad * 180deg/pi rad

rad cancel out

x * 180deg/pi

This still equals x because 180deg/pi = 1, but it's now expressed as a deg because that's the only unit left.

[Edited by - yaroslavd on December 3, 2004 12:52:23 AM]
Quote:Original post by mike25025
d / 360 will give a value between 0 (no rotation) and 1 (full rotation)

then multiplying that by 2pi to get rads because 2pi in rads is a full rotation

(2pi is a full rotation because the diamiter of a unit sphere is 2 and the cercumfrence is pi * diamiter)


Perfect answer! Thanks a lot, Mike!!!
Quote:Original post by yaroslavd
180deg/pi rad = 1
x rad * 180deg/pi rad
rad cancel out
x * 180deg/pi

This still equals x because 180deg/pi = 1, but it's now expressed as a deg because that's the only unit left.


Thank you!
You are welcome. Now how about that rating? [wink]
Quote:Original post by yaroslavd
You are welcome. Now how about that rating? [wink]


Wow, there is a rate system! Cool! [wink]

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