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I Forge Iron

Jr High Geometry U should know

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If you were too busy being fed up with the bewildering nonsense, here’s some genuinely useful bits you might have missed

Pi=3.14, just remember 3 is a close short measure 

Cross section of a round rod (area) is:

Pi x Radius x Radius (x length for volume)

So a 1” rod= .5 x .5 x 3.14= 0.785, note a 1” round rod can be hammered into a 3/4” square, a 1-1/8” round comes out to .9935”…handy to know off hand

Circumference of a circle is the whole Diameter x Pi, so 1” rod is 3.14” around, wondering how much kaowool for a round furnace, there you go


Steel weighs about 1/4lb/cubic inch, so a 1” round, 12” long weighs:

About 3/4” x 12”=9 cubic inches or about 2-1/4lbs


Pythagorean Theorem (a right, 90deg triangle):  (A x A)+(B x B)= (C x C)

If the Two legs of the square/right corner (A and B ) were 2” and 3”, then (2x2=4)+(3x3=9), so 4 + 9=13, put 13 into a calculator and press the square root button, C = 3.60555” (near 3-5/8”)

C is also the diagonal of a square or rectangle;

If you’re trying to square the corners of a square or rectangle, the diagonals are equal, make it so and voila, don’t even need to bother with calculating



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Welcome from the Ozark Mountains.

Lets see Jr. High, for me that would have been in 1954 and I've slept a couple of times since then, so I don't remember those Geometry formulas. However, if and when I need them, I know where to find them.:)

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus


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Welcome aboard, glad to have you, if you put your general location in the header you'll have a much better chance of meeting up with members living within visiting distance.

To play devil's advocate. If you're using a calculator then using the correct factors is less work than slopping your work and having to correct the mistakes in your product. I'll bet the scrap yard LOVES people who use 1/4lb/cu ft. when they drop off a load.

Pi is not 3.14, using that would be considered too sloppy for an approximation in jr. high. Like we were allowed to use approximations in jr. high. Answer 3.14 if asked what pi is and you'd have extra homework that night.

3.rsq. isn't even  close unless maybe you're guesstimating how much manure to buy for the new garden.

I don't know of anybody experienced who doesn't use the 3 4 5 ratio to check square corners if they don't have a square. 

Area of a circle is 0.7854.dsq. which is accurate to more decimal places than anyone outside NASA really needs.

Of course maybe you are demonstrating the level of modern high school math which is frankly frightening. 

Okay, enough of that, it's too easy. How about introducing yourself and asking some questions?

Frosty The Lucky.


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  • 4 weeks later...
13 hours ago, Nobody Special said:

Frosty that you only celebrate Pi day on March 14 at 03:49 a.m.

No Mr. wizard I use 0.7854d sq. so I don't have to roll my eyes at pi day sillies. 

No comment Steve. . . Glad you're getting some down time. :rolleyes:

Frosty The Lucky.

P.S. Take your time thinking up something new. Today is the last day of the Arctic Winter Games and the Curling Finals, I'll be back but maybe not today.

Good curling all!

Frosty The Lucky.

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While I like all kinds of pie I almost never indulge anymore. Since developing type II diabetes I've had to lay off baked goods almost entirely. If Deb has pie, cake, etc. I might have a bite and watch my blood sugar shoot up 50pts or so, happily it foes back down suddenly after a while but no more pie, cake, ice cream, etc. for Frosty. :(<sniff>

Frosty The Lucky.

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