FWIW - km to miles conversion factor on a four-banger calculator « Next Oldest | Next Newest »

 ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-17-2011, 07:37 PM ...or when you HP lacks this conversion factor and you don't remember it (1.609344). Enter 45 then press the SQRT key three times and voilà: `1.609353928` The error when converting the distance from the Earth to the Moon is than then one mile and a half. When converting greater distances such as the Earth-Sun distance you might want to subtract 1/450 from 45 before extracting the eighth-root: `1.609343993` The error will be inferior to half a mile. My 2 cents (every time someone uses this to convert km to miles :-) Edited: 17 Oct 2011, 7:41 p.m. ▼ bill platt Unregistered Posts: 2,448 Threads: 90 Joined: Jul 2005 10-17-2011, 07:53 PM That's pretty funny! And easier than doing (0.3048m per feet ) 5280 feet per mile etc. Paul Dale Unregistered Posts: 3,229 Threads: 42 Joined: Jul 2006 10-17-2011, 07:56 PM I just use eight fifths as the conversion factor. Much larger error but easy to remember :-) - Pauli ▼ designnut Unregistered Posts: 264 Threads: 65 Joined: Sep 2007 10-17-2011, 08:09 PM Driving in Europe I found KM a much more usable distancce measure. I liked the 100M posts along rural roads. A mile is simply too large for my measuring stick. Are we ever going to get on the world standars? Sam ▼ bill platt Unregistered Posts: 2,448 Threads: 90 Joined: Jul 2005 10-17-2011, 08:16 PM Who wants centimeters when you can have an inch? Who wants kilometers when you can have mile? Who wants kilograms-force when you can have pound? Who wants kilograms when you can have slugs? Who wants deciliters when you can have cups? Who wants cubic decimeters when you can have pecks? And finally, wouldn't you miss chains, rods, furlongs and leagues not necessarily in that order? See what I mean :-) ▼ db (martinez, ca.) Unregistered Posts: 1,322 Threads: 115 Joined: Jul 2005 10-21-2011, 10:59 PM Bill; did you realize that 10 chains equal one furlong? And that 100 links are one chain? We have the beginnings of a new metric here. All we need is something that's 6.6 feet (let's call that the basketball player), the 6,600' furlongic mile, and the micro-furlong for fine work. We have surveyors, horse lovers, cricket players, and all those desirous of knowing just how big "hells half acre" really is - all firmly on our side. We can't loose. It can't be any more contrived than the metric system. ▼ Walter B Unregistered Posts: 4,587 Threads: 105 Joined: Jul 2005 10-21-2011, 11:43 PM :-D Shall I quote Mikhail Gorbatchov? David Hayden Unregistered Posts: 528 Threads: 40 Joined: Dec 2008 10-18-2011, 01:12 PM Quote: I just use eight fifths as the conversion factor. Much larger error but easy to remember :-) I use the same factor and some tricks to convert between miles and Km in my head. Use these to make friends and get dates (well, make friends anyway... nerdly friends). The trick is knowing that to get 0.6X you take half of X and add 1/10th X. So 0.6*52 = 26 + 5.2 = 31.2 mi->km: multiply by 1.6. So 52mi = 52+26+5.2 = 83km km->mi: multiply by 0.6. So 52km = 31.2mi. John B. Smitherman Unregistered Posts: 256 Threads: 4 Joined: Sep 2007 10-17-2011, 08:09 PM Which is close to the golden ratio of 1.61803399 John ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-17-2011, 08:19 PM Which is halfway between 8/5 and the golden ratio. Gerson. Egan Ford Unregistered Posts: 1,619 Threads: 147 Joined: May 2006 10-17-2011, 08:15 PM But I thought the definition of a four-banger was that it had only the primary four arithmetic operators. So, no square root key. :-) About 100 lbs ago I used to run 5K and 10K races. So I always remembered 10K ~ 6.2M. ▼ bill platt Unregistered Posts: 2,448 Threads: 90 Joined: Jul 2005 10-17-2011, 08:17 PM Oh! You are right! It is a 5-banger. Also known as an Audi. Dan W Unregistered Posts: 185 Threads: 20 Joined: Apr 2007 10-17-2011, 08:45 PM Quote: But I thought the definition of a four-banger was that it had only the primary four arithmetic operators. So, no square root key. :-) About 100 lbs ago I used to run 5K and 10K races. So I always remembered 10K ~ 6.2M. Yes but I recall there is also a clever iterative way to do square root approximations on a 4-banger. But I forget what the trick is. And then it would have to be done 3 times. Sort of a mathematical Rube Goldberg process I suppose. Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-17-2011, 09:05 PM Quote: About 100 lbs ago I used to run 5K and 10K races. So I always remembered 10K ~ 6.2M 4 years and 15 kg ago I ran 2400 meters in 10m53s in a proof I had to run the distance in 11m03s at most for a perfect score. I never asked myself why exactly 2400 meters, but I realize now this is approximately one and a half mile. M. Joury Unregistered Posts: 756 Threads: 31 Joined: Aug 2010 10-17-2011, 10:29 PM Clever. In testing the conversion accuracy just for fun) with a relatively large number the nearest calculator I had to hand was a HP39gs and in running the conversion I was reminded that HP got the conversions backwards on that machine. ->MILE converts *FROM* miles to KM and ->KM converts *FROM* KM to Miles. ROM Version 2.22. Cheers, -Marwan ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-18-2011, 12:26 PM Interesting. What other HP calculators offer direct km->mi and mi->km conversions? I mean without having to append the units as in the 48/49/50g. Gerson. ▼ Marcus von Cube, Germany Unregistered Posts: 3,283 Threads: 104 Joined: Jul 2005 10-18-2011, 12:59 PM WP 34S does it. Chris Randle (UK) Unregistered Posts: 136 Threads: 22 Joined: Aug 2010 10-18-2011, 04:03 PM 35s dbatiz Unregistered Posts: 64 Threads: 8 Joined: Oct 2006 10-18-2011, 01:25 AM It may seem like the long way, but the only distance conversion I've successfully commited to memory is 25.4mm=1 Inch. Being a definition, it is exact. From there, any four banger can get my any conversion I need in just a couple of steps. ▼ Paul Dale Unregistered Posts: 3,229 Threads: 42 Joined: Jul 2006 10-18-2011, 02:12 AM I'm not so sure myself. How many links in an atto-parsec? :-) I love good old imperial measurements, there is an obtuse unit for everything ;-) Well, I love them so long as I don't have to actually use them that is. - Pauli ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-18-2011, 07:20 AM I would always prefer the International System, except in situations like the following: The woods are lovely, dark and deep, But I have promises to keep, And miles to go before I sleep, And miles to go before I sleep. -- Robert Frost Here, the metric system would spoil the metric of the poem :-) Gerson. ▼ bill platt Unregistered Posts: 2,448 Threads: 90 Joined: Jul 2005 10-18-2011, 07:51 AM Haha very clever! ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-18-2011, 09:19 AM The woods are lovely, dark and deep, But I have promises to keep, Kilometers to go ere sleeping, Kilometers to go ere sleeping. No conversion factor will do. This looks quite terrible! ▼ Mike Reed Unregistered Posts: 82 Threads: 15 Joined: Jan 2008 10-18-2011, 10:22 AM Gerson; how about this?? The woods are lovely, dark and deep, But I have promises to keep, And far to go before I sleep, And far to go before I sleep. Generic, and still in the correct meter! ;o) ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-18-2011, 10:31 AM That's better. Just found this one: I was just listening to a Bee Gee's song in the car and noticed something even worse: it appears there are no rhymes for kilometer, except speedometer, odometer, magnetometer and the like. "The preacher talked to me and he smiled, Said, come and walk with me, come and walk one more mile." Edited: 18 Oct 2011, 12:47 p.m. Matt Fegenbush Unregistered Posts: 20 Threads: 3 Joined: Sep 2011 10-18-2011, 11:09 AM Are you talking about links in a surveyor's (Gunter's) chain or an engineer's chain? I only work in surveyor's chains since I consider engineers chains an abomination. Kiyoshi Akima Unregistered Posts: 325 Threads: 18 Joined: Jul 2006 10-18-2011, 01:24 PM If you're on a scientific calculator and can tolerate an order of magnitude more error (half a foot in a mile), just use the natural logarithm of 5. You'll be off less than fifteen miles when you get to the Moon. Patrice Unregistered Posts: 274 Threads: 23 Joined: Sep 2007 10-18-2011, 02:19 PM Weird, I always thought a Mile was 1.852 Km . As far as I remember, the 2 Miles have already killed! Patrice ▼ Marcus von Cube, Germany Unregistered Posts: 3,283 Threads: 104 Joined: Jul 2005 10-18-2011, 02:35 PM Patrice, you seem to be talking about nautical miles. ▼ Patrice Unregistered Posts: 274 Threads: 23 Joined: Sep 2007 10-18-2011, 04:46 PM The only one I know about :) Cristian Arezzini Unregistered Posts: 372 Threads: 42 Joined: Mar 2011 10-19-2011, 04:24 AM Didn't four-bangers only have the four operations, so no square root? :P Cristian ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-19-2011, 06:45 AM Ciao Cristian, My definition of "four-banger calculator" matches the one I've found here: "a calculator that only does addition, subtraction, multiplication and division – sometimes with square root and percent keys added for good measure." The greek word for table is trapezi (in a loose transliteration), which originally implied a "four-footed" furniture. Tables now have three, two or even only one foot, yet in Greece they keep on calling it trapezi :-) Gerson. Jeff Kearns Unregistered Posts: 222 Threads: 21 Joined: Oct 2006 10-19-2011, 10:30 AM As a Canadian engineer raised in both English and SI/Metric systems, I find this post at once funny and coincidentally of interest. Funny: Upon reading the post, I wondered why one would one bother remembering such complicated numbers when the 'standard' to use is 1 in equals 25.4 mm? It is easy to remember and a breeze to use on a 4-banger. Interesting: Shortly after reading this post yesterday, I saw an el-cheapo 'scientific 180 function' calculator for \$1.50 at Giant Tiger that had the conversion factors listed on the inside cover of the calculator. It said 1 in = 2.53995 cm (or something close to that...). I bought the calculator for my 7 year old and ended up getting if for free as they overcharged me by 100% at the check-out... I have since researched the conversion factors and cannot find any reference to this bizarre conversion. Any thoughts on this? I do not have the calculator with me. Jeff Kearns ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-19-2011, 11:25 AM Quote: 1 in = 2.53995 cm (or something close to that...) You have a good memory! That's the same number that appears here and elsewhere. The exact 2.54 conversion factor derives from the international yard, defined in 1959 as 0.9144 meters (0.9144/36 = 0.0254). According to Wikipedia, the new international foot "was 2 ppm shorter than the previous U.S definition and 1.7 ppm longer than the previous British definition." However 2.54 cm is about 20 ppm longer than 2.5399 cm, a mistake perhaps. Gerson. Edited: 19 Oct 2011, 11:47 a.m. ▼ Marcus von Cube, Germany Unregistered Posts: 3,283 Threads: 104 Joined: Jul 2005 10-19-2011, 12:40 PM Quote: 1 inch (in) | 2.53995 centiliters (cm) :-) ▼ Gerson W. Barbosa Unregistered Posts: 2,761 Threads: 100 Joined: Jul 2005 10-19-2011, 01:29 PM Sharp eagle's sight! "With a diverse population of over 170 million souls, Brazilians are very happy people, spontaneous, enthusiastic and high-spirited who tend to live for the moment and who know how to enjoy themselves" They've forgotten to add the following: and never waste their time by checking and double-checking their websites contents. :-) Edited: 19 Oct 2011, 1:47 p.m. bill platt Unregistered Posts: 2,448 Threads: 90 Joined: Jul 2005 10-19-2011, 03:14 PM I wonder if this relates in any way to the "survey foot" ? And didn't there used to be some sort of abstruse issue with ml not equaling cubiccentimeters? ▼ Martin Pinckney Unregistered Posts: 1,248 Threads: 33 Joined: Aug 2007 10-19-2011, 03:49 PM Yes. The U.S. Survey Foot was based on the old definition of the meter. So when the meter definition changed, two foot definitions were needed, else all the existing base of survey work would be off.

 Possibly Related Threads… Thread Author Replies Views Last Post HP 35s polar/rectangular conversion CD Dodds 6 2,648 11-28-2013, 02:39 PM Last Post: Dieter [WP 34s] Pressure Conversion Factors Timothy Roche 8 3,131 11-04-2013, 07:17 PM Last Post: Dave Shaffer (Arizona) More programs for polar-rectangular conversion on HP Prime Michael de Estrada 4 1,973 11-04-2013, 12:43 AM Last Post: Michael de Estrada HP Prime Collect/Factor difference bluesun08 3 1,491 10-29-2013, 09:36 AM Last Post: Eddie W. Shore 33s, 35s & 42s--The Timex(R) Factor Matt Agajanian 7 2,247 09-13-2013, 12:28 AM Last Post: Matt Agajanian HP Prime: Conversion factors Paul Townsend (UK) 19 5,000 08-27-2013, 09:19 AM Last Post: Nigel J Dowrick Finding the largest prime factor on the 15c Evan Gates 2 1,242 10-03-2012, 11:17 AM Last Post: Thomas Klemm WP34S conversion, yet another but with a difference Geoff Quickfall 23 5,933 06-22-2012, 02:54 PM Last Post: Marcus von Cube, Germany [WP-34s] Conversion proposal Alexander Oestert 19 4,762 06-15-2012, 05:36 AM Last Post: fhub [WP-34s] IR conversion of 20b Alexander Oestert 3 1,526 05-18-2012, 05:38 PM Last Post: Harald

Forum Jump: