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Author: Subject: Trigonometry calculation please
snapper

posted on 21/2/18 at 08:52 PM Reply With Quote
Trigonometry calculation please

One for you clever people.
I have a measurement of 125mm between 2 points on the circumfence of s circle
There are 6 equidistant points around the circumstance
What is the diameter or PCD of the circle?





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craigdiver

posted on 21/2/18 at 09:09 PM Reply With Quote
quote:
Originally posted by snapper
One for you clever people.
I have a measurement of 125mm between 2 points on the circumfence of s circle
There are 6 equidistant points around the circumstance
What is the diameter or PCD of the circle?


not enough information - is the 125mm between two adjacent studs?

To calculate the PCD (mm) you divide the measurement between centres of two adjacent studs and devide by 0.5. This will only work fir 6 stud hubs.





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adithorp

posted on 21/2/18 at 09:11 PM Reply With Quote
If the 125 is measured in a straight line between 2 adjacent of the six points then the PCD is 250mm.

If its a measurement of the distance around the circumference (which I doubt you mean) then PCD = 6x125 / pi = 238.732 ...I think

[Edited on 21/2/18 by adithorp]





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DanP

posted on 21/2/18 at 09:13 PM Reply With Quote
The diameter is 250mm by my calcs - use the COSINE rule and make a=b (i.e. the radius), c is 125 and C = 60 (360 degrees/6)
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daviep

posted on 21/2/18 at 09:18 PM Reply With Quote
If the 125mm is a straight line between two adjacent point then the diameter of the circle will be 250mm.

If there are 6 points on the circle then there is 60 degrees between each point and the triangle formed between the centre of the circle and two adjacent points will be equilateral ( all angles and lengths the same) so the radius will also be 125mm.





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bi22le

posted on 21/2/18 at 11:15 PM Reply With Quote
quote:
Originally posted by daviep
If the 125mm is a straight line between two adjacent point then the diameter of the circle will be 250mm.

If there are 6 points on the circle then there is 60 degrees between each point and the triangle formed between the centre of the circle and two adjacent points will be equilateral ( all angles and lengths the same) so the radius will also be 125mm.


That is what I was thinking.

Imagine it like a 6 slice pizza with it slice having the cyst cut off in a straight line, from corner to corner. The triangle that is created will have even lengths sides. 125mm rad, 250mm dia.

Now eat the pizza, dipping the crust in garlic and herb sauce!





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gremlin1234

posted on 22/2/18 at 12:26 AM Reply With Quote
quote:
Imagine it like a 6 slice pizza with it slice having the cyst cut off in a straight line, from corner to corner. The triangle that is created will have even lengths sides. 125mm rad, 250mm dia.

Now eat the pizza, dipping the crust in garlic and herb sauce!
I guess autocorrect changed crust :-((( but enjoy pizza

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907

posted on 22/2/18 at 03:55 AM Reply With Quote
I can never eat 6 pieces of pizza, so I cut mine into 4.








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snapper

posted on 22/2/18 at 06:56 AM Reply With Quote
Thank you, you clever people
For the others, mines a double pepperoni and I can manage 6 slices but not 8





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