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Trigonometry calculation please
snapper - 21/2/18 at 08:52 PM

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?

craigdiver - 21/2/18 at 09:09 PM

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.

adithorp - 21/2/18 at 09:11 PM

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]

DanP - 21/2/18 at 09:13 PM

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)

daviep - 21/2/18 at 09:18 PM

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.

bi22le - 21/2/18 at 11:15 PM

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!

gremlin1234 - 22/2/18 at 12:26 AM

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

907 - 22/2/18 at 03:55 AM

I can never eat 6 pieces of pizza, so I cut mine into 4.


snapper - 22/2/18 at 06:56 AM

Thank you, you clever people
For the others, mines a double pepperoni and I can manage 6 slices but not 8