I can't remember the formula for the life of me.
If a dish is almost 3 ft across and I want to segment it like an orange into 10
segments how do I calculate how wide each will be at the rim?
So I end up with a dish that has 10 sides.:)
I'm math clueless.
Thanks. I can't measure around because it ain't made yet.<g>
I need to cut ten pieces of steel to form a ten sided form that will fit exactly
inside a 3 foot circle. I need the distance between the points as a straight
line. so if it section is shaped like a bow I need the length of the string.
Does this make any sense?
Thanks for the responses guys. The circles are all less than my example of 36",
the biggest is just over 35 3/4 on the inside.
Some are as small as 12"
I will try some of the formulas and see if I can figure out which one is easy to
use.
I also need to calculate on 6, 8 and 12 segments.
Thanks I'll keep that in mind if I can't figure this out.
Like pumpkins the sizes will always change.
I would like to be able to do segments that are not equal as well.
If I can't figure out the formulas I will fire up a cad program and see if it
helps.
It's the math terminology that drives me crazy.
Beyond the terms radius and circumference I'm clueless.
I'm sure somewhere there was a term posted for the straight line distance
between two points on the edge of a circle but I'm still unsure what that term
is.
I haven't had time to digest all the posts yet.
term
A "chord", as opposed to the curved part, which is generally called the
"arc".
An old Artilleryman will tell you that one mil of angle will subtend an
"arc" of 1 meter at 1000 meters .. but, as in your case, it is really the
"chord" that is the distance on the ground you're after when adjusting
artillery fire. With the roughly 50 meter effective zone of a HE 105mm
round, the difference between the "chord" and the "arc: is moot ... but you
need a bit more precision than that.
... I mean, ya gotta put this stuff in perspective with those things of
which you are intimately familiar. :)
And if the gun was on a ship....... LOL. I don't think I will ever forget
the length of the equation we used in Physics when determining when to pull
the trigger and when will it hit if the seas were rough and the ship was
traveling.
Keep an eye on alt.binaries.pictures.woodworking your quick formula will show up there as soon as I have it written.

PDQ
 wrote:

 >Burt wrote:
 >>
 >> I can't remember the formula for the life of me.
 >> If a dish is almost 3 ft across and I want to segment it like an orange into 10
 >> segments how do I calculate how wide each will be at the rim?
 >> So I end up with a dish that has 10 sides.:)
 >>
 >> I'm math clueless.
 >
 >perimeter = pi * diameter = 3.1415926 * 3 = 9.42478 ft
 >
 >Or, just measure around and divide by 10...

 Thanks. I can't measure around because it ain't made yet.<g>
 I need to cut ten pieces of steel to form a ten sided form that will fit exactly
 inside a 3 foot circle. I need the distance between the points as a straight
 line. so if it section is shaped like a bow I need the length of the string.
 Does this make any sense?
Burt (in snippedforprivacy@4ax.com) said:
 I can't remember the formula for the life of me.
 If a dish is almost 3 ft across and I want to segment it like an
 orange into 10 segments how do I calculate how wide each will be at
 the rim?
 So I end up with a dish that has 10 sides.:)

 I'm math clueless.
Burt...
Each of the sides will be 36" * sin(360 degrees / 20) or approximately
111/8"

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html
Too much work and I don't get the same answer anyway. (PI * 36 / 10) PI * 3.6 = 11.3097312 etc. etc. etc. Significantly more than 1/8 inch
difference, it's over 11 1/4 inches.

I can find no modern furniture that is as well designed and emotionally
satisfying as that made by the Arts and Crafts movement in the early years
Ed Clarke (in snippedforprivacy@individual.net) said:
 Burt (in snippedforprivacy@4ax.com) said:

 I can't remember the formula for the life of me.
 If a dish is almost 3 ft across and I want to segment it like an
 orange into 10 segments how do I calculate how wide each will be
 at the rim?
 So I end up with a dish that has 10 sides.:)

 I'm math clueless.

 Burt...

 Each of the sides will be 36" * sin(360 degrees / 20) or
 approximately 111/8"

 Too much work and I don't get the same answer anyway. (PI * 36 /
 10) = PI * 3.6 = 11.3097312 etc. etc. etc. Significantly more than
 1/8 inch difference, it's over 11 1/4 inches.
Not too much work if your calculator has trig functions. My Windows
calculator came up with 11.124611797498107267682563018581", which
misses 111/8 by only 0.0004".
Pi * 36 / 10 would be the arc length of the segment, while 36*sin(18)
is the chord length. The difference is
0.18512175542514839078295316122472", somewhere near 3/16"  so the
extra effort may be worthwhile :)

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html
Your answer is to a question that was not asked. Had the OP asked what the
length of the exterior of the segment was you would have been correct.
However the OP asked how wide the segment would be. The widest part would
be the distance between the two closest points of that triangle shaped
segment. That distance between those two points is approximately 11.125".
If he were building a 10 segment, flat circle you would be right on
but he said "dish". I suspect he needs the other sides's dimension
as well. More information is necessary to figure it out. How deep
is the dish and does it have an elliptical section or is it part of a
sphere? What is the dish for exactly? There are myriad possibilities
when you say dish so there is no way to give a (complete) correct answer...
Phil Davis
247PalmBeachRE.com
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