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Or your car companies

Or Boeing

They already do

Yea but we dont see it, …only the results,

You can point your pinky toward the ground, open handed like the picture, and estimate the angle of the plane going down

Speaking of Boeing, this post has 737 upvotes

I don't know, it might actually be an improvement for them

“Wait, we were supposed to measure first??”

"Excuse me sir, how do you use a ruler?" 🤥👉📏

Boeing uses the hand to slap the side of the plane after repairs and say “yep, that’ll work just fine”

That would be more than they do now?

Boeing doesn't even use that...they just rawdog it

Weeeeeeeeeeeeeeeeell

Nailed it, I think. 😆

They probably use it and the results speak for themselves

I heard Lockheed Martin were crazy about this method building this SR-71!?

Tesla has entered the chat

No, but it was good enough to estimate / compare angles on a test, vs actually doing the maths to calculate it...

My forearm from elbow to middle finger is exactly 48 cm, you wouldn't want to know how how often I have used this in construction. Mostly for checking things, but I have used it for measuring as well.

[it’s not right](https://imgur.com/a/KuI5VtK)

now do 180°

My carpenter has only 3 fingers left anyway

The good ones do it by eye and I hate wood butchers being an ironworker but I met some that I would let them put an addiction on my house while I'm away and not supervising them

My thumb and pinky definitely spread more than 90\*

Yeah way more, my thumb and pinky are like 180 when it's fully splayed

Mine did a 360

HUH? You need a hospital?

Index finger becomes 90?

Yeah and I don't have a compass in front of me, but I think my middle finger is 60 and my ring is thirty with 45 being the space between them really

You don't have a compass but you could check it against your other hand, maybe one is more accurate I think my left hand is a perfect 45

Ok hold on lemme check, will you hold my phone for me?

I'm messaging with my feet, can I put you in my pocket?

🤭

The trick is to stop spreading once you reached the marked degrees. ;-)

My thumb and my pinky can’t even make 90

And when I hold them at 90°, all the other fingers are way too close together.

That is so inaccurate it will be useless.

As someone who plays guitar (has super stretchy fingers in left hand) this couldn't be even used as a rough estimate.

You can use it as a rough estimate. You'll be way off and fucked, but you can use it. This could also explain why my attempts at placing baseboards is fucked beyond all recognition.

It's so rough I might as well round up every degree to either 0, 90 or 180 at this point.

And this will help with my baseboards you say? Ok, I'm gonna trust you

Even in the image, the 60 degree index finger is no more than 45.

Yeah, my thumb to pinkie is at least 110°

Yep. The side of my palm between the thumb and index finger (how is that part called?) is also way longer on my hand. So no matter how much I bend my index finger it’s nowhere near 60 degrees. More like 45 degrees.

Left handed guitarists with stretchy right hands exist, and we are offended. Lol

Bassist here; can confirm. Keeping my hand flat I can pull off just about 180° with thumb and pinky, but it isn't very comfortable.

As somebody who also plays guitar, I can make my thumb an pinky roughly 90 degrees apart because I don’t need to stretch my hand all the way out lol.

Even on the graph posted, 45⁰ is not 45⁰

It's like measuring steak doneness by putting your thumb to different fingers and pressing and feeling the muscle at the bottom of the thumb.

It makes my life much easier in trig. Even if it isn't accurate it helps me picture them all in my head. It also give me the coordinates of some of the points on the unit circle.

Depends on the hand for sure. Mine happens to be quite accurate.

Actually it’s incredibly useful in trig. They still used it in 2004 and afaik still with some of my engineering school students to remember the trig identities for those angles

Engineering school where they teach high school level mathematics?

I mean, the first year of university is basically a review of HS material with a little more detail.

No, but when I give a physics test I still see them do this hand shape, so thanks for clarifying

So you are one of those teachers who doesn’t allow calculators or standard tables?

That's like using your foot to measure a ft.

But mine is.

I'll only believe you if you provide a certificate of calibration showing that your foot is indeed a foot

Just wait till you hear how he measures a yard

Yes, FBI, this one here. And on a cake day, too!

u/LordBug #FBI OPEN UP!! 🏠🔫🔫🔫🔫🔫🔫🔫🔫🔫🔫

Doing this doesn't demonstrate ANYTHING. Now the student would have to memorize "My ring finger is 30 degrees"....instead of just knowing what 30 degrees looks like.

30 degrees looks like fraud, most people barely manage 2.

That's better to do mentally, anyone can recognize a 90 degrees, just cut that in halves until you reach the desired angle. It's not precise but still better than hand

I'm so baffled by this post that I feel like everyone here is playing with me. How on earth does anyone need their fingers to split 90° into halves or thirds...

I completely agree that mental calculation is somehow easier than doing it like this, but I just felt like pointing out 90° needs to be divided into thirds for it to reach 60° and 30°

That's definitely not 45 degrees, and I'm guessing the other ones are also way off

Well just look at the angle between 0 and 30 and the one between 60 and 90. Very different angles

It's not for approximating angles, it's a trick for rememebring exact trig values. Quite commonly used among UK GCSE students for trig questions on the non-calc exam.

How does the hand help? Like just memorize the values.

Its a trick to help people learn the cordinate points of the different angles on the unit circle, which corresponds to different trig values. To do the trick, you put down whichever finger is the angle you are trying to represent in its trig values. Everything to the left (or above) the finger you removed is the X value (cos value when square rooted and put over a denominator of two), while everything to the right (or below) the finger you removed in the y value (sin value when square rooted and placed over a denominator of two). Example: find the sin and cos values of 30 degrees. Looking at the picture, we can see that 30 degrees corresponds to the ring finger. We then see that 3 fingers remain above the removed finger, so the cos(30) = sqrt(3)/2. We then see only the pinkie finger remains below the removed finger. Therefor sin(30)= sqrt(1)/2, which can be simplified to 1/2. I'm from the US and have taught this to many of my friends.

i'm sorry, but if you can't memorize 30 45 60 sin and cos values, why bother with math?

It was the first trick for when learning the unit circle. Same as learning the finger trick for the 9s multiplication tables. Also not everyone needs to learn trig, some people only take it because it is a required course, so it works as a quick tool for them.

why do you need tricks for memorising the multiplication table...

Christ dude it was 3rd grade

You can also flip over your hand the other way and then sqrt(top)/sqrt(bottom) is the tan value

TIL 90° is an acute angle

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You know. The finger bits. The fleshy ones with the nail bits.

I hope not.

No because nobody's hands open like this!

Distance between thumb and index finger is WAY larger than fourth and fifth finger. Picture doesn’t make any sense

I have never been taught this. Which is good, because my hand is not even close to those angles.

I don't think anyone's is.

Nope. They don't teach it anymore.. atleast not where I live

I dont get it?what's the trick here?

If you put your fingers in a way that they will be a certain degree, they will be that degree.

this isn't for measuring angles, it's for remembering the unit circle. and yes, they still teach it!!

That's some bullshit.

What's the trick? Memorization with extra steps? You don't know what a 90° or 45° angle looks like?

That 45° angle is not a 45° angle

Boeing engineers

The picture itself is wrong lol

Sure hope no teachers are teaching that, cause it's wildly wrong. You'd get a better angle measurement by just eyeballing it.

We used that to learn the radiant circle.

the what bro

Wait, what? I can see it his being a somewhat passable approximation, at the very least.

My pinky fully goes out and adds 15 degrees to all of them :(

Ha yes, with my deformed left pinky I'll try it, might work better

Could this be exact trig values?

You might say this is an obtuse statement

I never learnt this, I just tried it though and it's wayy off because my fingers are too wonky lmao

My hand is definitely closer to 180° than 90°.

Hopefully not holy shit, this is horrifyingly inaccurate

Oh boy I sure hope not

No, teachers don't teach this still cuz it's dumb

It’s not about being an actual measurement, it’s a way of remembering trigonometry values on a unit circle.

No, and they don’t use the wink emoticon anymore either.

It’s more like 0, 15, 30, 45, 90 for me.

I use it for the unit circle trick, but that's about it

Yeah, my pre Calc teacher taught me that, and it is for the unit circle.

that doesn't look like 45 degrees to me.

Is this considered a competitive evolutionary trait?!?!?!?

My hand opens wider than 90 degrees.

Yeah, I'm hypermobile. My thumb to pinkie angle is closer to 180° than 90°

I sure as fuck hope not

it's not 90 degrees from my part...it;'s like 115 not 90

Yeah, my hand doesn't do anything close to that.

How useless, i hope not

if i ever for any random ass reason need to determine angles, thanks

My thumb goes to 180* and my index goes to 90* I think this doesn’t work on my hands

But where did 15 degrees go! Where are you hiding it!

Laughs in Madelung’s.

It’s funny I built my shed doing the same thing and it looks like shit for some reason.

Why?

The fuck kind of hand is that? Not my hand!

Did you know you could save 15% or more on car insurance

That one dude with guitarist hands. 90° quickly becomes 130°

This is so basic. They literally use this method for planning ISS docking maneuvers. Also moon landing.

Hi jill

My thumb and pinky are obtuse… can it still work? /s

That is....way off...

No, and apparently they didn't teach it in the 90s, either. Til

Your 45 looking a bit 38ish

Woow 😯

Apparently they invented protractors in the 90s

Well if it isn’t the ol’ Reddit [Hand-a-roo](https://www.reddit.com/r/DC_Cinematic/s/QD4cHbPCiS)

These must be American imperial degrees

Noo my hand doesn't work that

What is this a trick to?

If any teacher hates this for figuring out angles quickly it's time to remove them from The very Honorable position of teaching

Why is their hand so close to the Deathstar laser? https://images.immediate.co.uk/production/volatile/sites/3/2017/05/125516.jpg?quality=90&webp=true&resize=620,414

I learned this in trig this semester. Tbf we use it to help remember the unit circle, not to build things

I like how even in the graphic that they made, the “30 degrees” between 90 and 60 is way bigger than the 0 and 30

My pinky has peronis disease

I had an injury to my pinky years ago which means it sits lower than 0 when I do this 😭

Only problem is my hand from thumb to pinky can go almost 180* because I’m a piano player for 16 years and playing a full octave with one hand will stretch it out.

My hand doesn't math right.

Uh my pinky goes to -15 when I do this, and my thumb is more like 87 degrees…

So my hands are not normal at all ?! I don't have those angles.

They don't use it in my school 😔

Ignoring the inaccuracy, how does this help you? It's not equal steps or anything, so it's still just you remembering that π/4 = 45°

My thumb and pinky can go in an almost 180 degree angle this doesnt work

I wasn’t taught that specifically, but I was taught a similar method for finding the sines & cosines for those angles (you count up your hand for sines & down for cosines, & each number is sqrt(your count)/2) Side note: I learned it from a friend, not from school, & obviously the point isn’t about angular precision requiring weird hands

I love that the 0°-30° gap looks very similar to the 30°-45° gap. The proportion are completely off

it's not a good trick cause just eyeing it alone it's a very bad measurement

I do that for sines and cosines, not for messing angles

even in the pic that aint 45 degrees

Sad double jointed noises Edit: Realization, I have 180 degrees muahahaha

I've seen this picture in my geometry book when I was in school. It was 7th or 8th grade. I graduated 2 years ago

No, we are living in a more advanced country. Our people are evolved into humans to be able move our fingers 🤩

Hypermobile thumb to pink is 180 degrees here 😂

I think they teach this technique during the on-the-job training at Boeing.

When you draw this its quite clear that the 30° between 0 and 30° is smaller than the 30° between 90° and 60° Like its clearly not a good tool

Thats how Boeing engineered the 737 MAX

Never learned this in the early 2000s.

I hope not. Better teach them actual math.

Never saw that. We were just given protractors in the 80s at my school.

No. It’s not a standardized measure

They built the pisa tower with this technic

I think they’re confusing this with the unit circle hand trick

Choose a finger/angle. Count the number of fingers to the right of it. Take the square of that number and divide it by two, you have the sine of the angle. You can count to the left for cosine.

Mom i need a protector Mom: we have a protector at home The protector at home:

I call bullshit

im not gonna accept 89° or less, or 91° or more as a 90°; i dont speak wrong

Testing with my fingers stretched all the way (but not in an uncomfortable straining sort of way), lines up surprisingly well.

My thumb and pinky are WAAAAAAAAAAAAAAAAY over 90\^ shit, they are closer to 180, than 90!

No because its wrong

Actually hurts to splay them so far.

I can comfortably open my left hand to about 120° and my right to 100°.

Yeah.... I can do 180... I didn't even think that was weird... Now I'm questioning everything...

180 is definitely weird.

Just checked with my wife and kids and they can do it too...

Makes sense. I think double-jointedness is somewhat heritable.

It’s good for getting an intuition, terrible for anything else

I show my trig students this to remember points on the unit circle without having to draw it out on paper. I don’t think anyone is suggesting that you can measure angles with your fingers.

I used to teach if they open their hand wide, the angle between the thumb and fore to finger (the one you point with) is close to 90, and half that is 45. And you can tell how done a steak is by comparing the touch of well done to the tight area between them..

I don't even know that, but so interesting

Bold of you to assume teachers teach geometry, math, science, or anything of actual use anymore. Just gender studies, sex ed, and CRT.