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On 2005-06-27, Morris Dovey wrote:
Burt (in ) 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 11-1/8" 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. -- 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 of the last century. |
"Morris Dovey" wrote in message ... Burt (in ) 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 11-1/8" -- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/solar.html 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 |
Ed Clarke (in ) said:
| On 2005-06-27, Morris Dovey wrote: || Burt (in ) 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 11-1/8" | | 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 11-1/8 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 |
Phil (in ) said:
| "Morris Dovey" wrote in message | ... || Burt (in ) 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 11-1/8" || || -- || Morris Dovey || DeSoto Solar || DeSoto, Iowa USA || http://www.iedu.com/DeSoto/solar.html || || | | 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... Burt also wrote: 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. I interpreted this to mean he wanted the straight line distance between adjacent points on a circle. Since circles are planar objects, I don't think deformations of the 10 segments enter into /this/ calculation, but I could be wrong ( and frequently am :-) -- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/solar.html |
Send me an email and I will send you a CAD drawing. Exact to 8 decimal
places (though the answers you got here are correct). Thought you might want something on "paper". Will send as PDF. "Burt" wrote in message ... Beyond my figuring skills and it has to be exact. :) Each of the points has to touch the inside of the 3 foot circle. |
"Ed Clarke" wrote in message ... 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. 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". |
"Morris Dovey" wrote in message ... Phil (in ) said: | "Morris Dovey" wrote in message | ... || Burt (in ) 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 11-1/8" || || -- || Morris Dovey || DeSoto Solar || DeSoto, Iowa USA || http://www.iedu.com/DeSoto/solar.html || || | | 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... Burt also wrote: 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. I interpreted this to mean he wanted the straight line distance between adjacent points on a circle. Since circles are planar objects, I don't think deformations of the 10 segments enter into /this/ calculation, but I could be wrong ( and frequently am :-) -- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/solar.html Morris, You are correct and it seems you are not to often incorrect. I often read your posts and you have some good solutions to the various problems posted. While a few others here were using their math skills, I cheated and used my CAD software to draw the problem and arrived at the length of (rounded) 11.125". Phil |
On Sun, 26 Jun 2005 22:10:09 -0400, "Phil" wrote:
"Morris Dovey" wrote in message ... Burt (in ) 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.:) 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... Nah, you're making it too complex. The difference in the two answers given is that one is the length from point to point on the circle (Morris's answer, approx 11.125"), useful if the OP is making ten segments with straight edges, and the other is the length of the curve (approx 11.3"), useful if the segments need tobe curved to fit the rim exactly. We don't need to know how deep the dish is to figure it out. |
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