Uff. Imperial measurements SUCK. they are completely impractical and hold no useful mathematical function--you have to do math to adapt your math to the scale. Who was the git who decided that "hey, we have 10 fingers, 10 toes, 5 points on a starfish...lets go with 12 inches in a foot."
I am trying to design a tilt-table to fit a small robot. (don't ask--it involves chickens in lab coats.) Now as you know the base of a tilt-table needs to be a very stable structure in order to prevent the table from falling over--the base needs to provide an exactly-centered fulcrum for a smooth, balanced tilt. And what's the most stable structure in geometry that can also act as a fulcrum? An equilateral triangle.
so i do the math. I start with a 30-60-90 triangle because i know if you mirror one you get an equilateral triangle with all the angles proper--60°--without a compass or a protractor. (i have both but i always manage to screw it up somehow.) I start...okay lets have a leg (hypotenuse) of 3 feet, which means the base would be a foot and a half (1'6") and the vertical bit would be (1/2x3') x (√3) ≈1.7 feet.
this is NOT 1 foot 7 inches. that would be too practical.
So i multiply 1.7(and some change) by 12. this gets me 20.78 inches. I know that 24 inches is 2 feet so 20 inches is 1'8". fine. now i have this .78 to play with.
Inches are divided into 16ths. as a carpenter who works with real materials of varying lengths, i have no need to cut down to anything smaller than a 16th of an inch because its not going to make much difference unless i'm building a lazer or something. i work with wood.
so i multiply .78 by 16 and get 12.48. i'm going to ignore the .48 because geez, man. so 12/16. on a measuring tape that comes up as 3/4. 1'8 3/4". Close to 1.7, but not quite.
Now that i've worked that out i realize that .78 is right near .75 which is 3/4, but it takes luck for that to work out. i mean if it came up as .6 i'd be lost.
this is so counter-freaking-productive. I like centimeters. You can do real math with them without adjustment. 1.7 cm is 1cm 7mm. or just 1.7 cm. unlike 1.7 feet which is 1' 8 3/4." REE TAR DED.
In a moment of idiocy, i drew my triangle...in centimeters. it just made so much more sense. and this would work fine except for the fact that my scale rule is in feet. so now i have to go back and draw it again using the other side of the ruler so i can do it to 1/2" scale so other carpenters in this country can understand it.
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The metric system is ace. I can honestly say that I have no idea what any of that means, I was never taught any imperial mesurements so my knowledge is pretty sketchy. Pretty much everything I use is metric.
I don't think you mean isoceles, an isoceles is a triangle with two angles the same, although perhaps right-angle triangles have a different name in the us.
hmm. I wonder how I knew that. I must have actually remembered something from GCSE maths. Crazy.
wow, you remembered something that i obviously didn't. i'll fix that.
I'm convinced America clings to the imperial system just because the French like the metric system lol!
It is ridiculous, i'm willing to bet that NASA uses metric when designing space craft! I dunno, I think the imperial system is just so archaic! it's like using cubits!
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