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1. Flaperon - Member

   Sorry to post up such a stupid question, but I'm running on caffeine and really struggling to find a quick way to do a really obvious maths question.

   Interpolation between two entries in a table:

   2250m 2500m
   ======|======
   69.15 | 72.45

   Obviously the mean of the 2250 metres and 2500 metres value (ie 2375 metres) is 70.8. How the devil do I find a simple way of getting the value for, say, 2350 metres.

   I have a physics degree and my brain seems to have shut down most of the important bits tonight.

   Posted 2 years ago #
2. rockthreegozy - Member

   2500-2250 = 250
   72.45-69.15 = 3.3

   3.3/250 = 0.0132

   So for 2375,

   125x0.0132 = 1.65 + 69.15 = 70.8?

   For 2350

   100x0.0132 = 1.32 + 69.15 = 70.47?

   Posted 2 years ago #
3. matthew_h - Member

   Divide the difference between 2500 and 2250 (ie 250m) by the 100m (from the 2250,2350 difference) to give the proportion of the difference between the 69.15 and 72.45

   Clumsy explaination for which I am sorry but that is kinda how it is done

   So for 2350m it is 100/(2500-2250) = 0.4 of the way between 2250 and 2500 so you need to work out 0.4(72.45-69.15) then add to 69.15

   Answer = 70.47

   Posted 2 years ago #
4. IanMunro - Member

   ((2350-2250/ 2500-2250) * (72.45-69.15))+69.15

   Posted 2 years ago #
5. Flaperon - Member

   Perfect, thanks... feel really stupid now!

   Posted 2 years ago #
6. postierich - Member

   What he said up there!!!!

   Posted 2 years ago #
7. mastiles_fanylion - Member

   42

   Posted 2 years ago #
8. avdave2 - Member

   don't forget to take away the number you first thought of.

   Posted 2 years ago #

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