Straight lines. Also two sets of parallel lines. This is one definition of a square, but not the common one.
I believe these lines are straight with a black hole at the centre.
straight, gay, lines are lines. let them be.
If that’s so, the angles are probably not right angles.
None of the angles looks wrong either
Can straight be defined in a nonlinear environment?
I would guess on a sphere these can be straight yes: The pole goes into the center of cicular thing and radius of the sphere needs to put the other arc on one latitude.
Euclid’s first postulate: Give two points, there exists exactly one straight line that includes both of them.
This only applies in 2nd order real space. Euclidean geometry aside, I agree with at least one line could exist between two points
Counterexample: North and Southpole on Earth.
No, it’s still accurate - the straight line goes through the center of the Earth. Only in coordinate systems where ‘straight’ is defined as following the curvature of a surface are there infinite lines between the North and South Poles… and that would be non-Euclidean geometry.
This shape could exist as a projection onto an upright cylinder, wrapping around the cylinder. The two straight edges go vertically along opposite sides of the cylinder. The curved lines wrap around the circumference. The lines are now straight and parallel on the net of the cylinder.
But we can go further: Imagine taking this cylinder and extending it. Wrap it into a loop by connecting the top to the bottom so it forms a torus (doughnut) shape. This connects both sides of the shape, now all “interior” angles are on the inside of the square, and all “exterior” angles are on the outside. The inside and outside just happen to be the same side.
Someone never had to deal with mathematical proofs, only layman’s definitions.
All properties of a parallelogram apply:
- Opposite sides are parallel
- Opposite sides are congruent
- Opposite angles are congruent
- Consecutive angles are supplementary
- Diagonals bisect each other
AND
- All angles are congruent
- All sides are congruent
- Diagonals are congruent
- Diagonals are perpendicular
- Diagonals bisect opposite angles
Of course, but such strict definitions only come about because smart people come up with examples like OP when you don’t add the full definition.
The interior angles need to be equal 🤓
Here you can see how things go haywire when skipping minor parts of definitions.
Does no one understand this is a joke, talking about parallel lines and mathematical proofs is pointless when its a fucking meme
It’s not pointless because you can laugh about a joke and then learn something about math.
They don’t cancel each other out. They can be at the same place and still work on their own.
I love memes that are funny on their own, but also provide discussion material.
Its wrong though so the joke falls flat
Didn’t realize jokes have to be literally correct
Just the good ones.
We do understand it’s a meme and a joke. Just not a very good one, because one can easily poke holes into it.
Just not a very good one, because one can easily poke holes into it.
That’s not how jokes work.
Depends on the joke.
No, it depends on if you have humor. Yes, humor is individual, I know. But people without tend to over analyze and try to pick the joke apart, often missing the point.
A joke doesn’t have to pass every technicality. You thinking it’s bad if it doesn’t, only applies to your humor (or lack there of).
Ooh, watch out, the humor police is here! Everything the deem funny is humor and if you don’t find funny what they do you don’t even have humor! Wee-ooo wee-ooo!
I can be presented with a bad joke without the urge to pick it apart. You couldn’t. Just saying.
And you cannot take criticism. Just saying.
(Also, I’m not picking apart the joke, I’m explaining why some people do.)
Its supposed to be absurd, taking it seriously makes the already bad joke even worse
It’s not about taking it seriously. The meme wants to be a technically correct-meme, where a thing fulfills another things definition and thereby could be deemed the other thing - which creates the absurdity the meme lives off of. But in order for that kind of humour, there cannot be obvious holes in the logic of the joke and these obvious holes are very present in this meme.
Any maths joke of this type will have obvious holes in it, that’s just how maths works
Well the text in the image of the “definition” of a square is clearly tailored to fit this joke, thats why the logic of what a square actually is doesn’t apply. Its like telling Diogenes that his chicken is not technically a human because it doesn’t have two hands and a nose.
Diogenes plucked that chicken to point out Platon’s definition of a human (being a bipedal, featherless animal) being flawed. This meme leaves out parts of the definition to enforce a joke. Two different situations.
Its similar enough, the definition is limited and therefore enables a joke to be made.
It’s not similar, it’s the exact opposite.
Or the fun part.
You’re having fun wrong!!1one
These are parallel too. They just look that way because they are project on to the euclidean plain.
Oh let’s get pedantic!
The curved edges technically have infinite “side”.
…and a square has four interior 90 degree angles.
…and based on the infinite number of sides for a curved line aspect, the “90 degree” angles would all be +/- the limit as it approaches zero, so never truly 90 degrees but always an infinite fraction away.
Someone knows more calculus than they are letting on…
Hey, I failed the highest level of calculus possible. Twice.
I’ll have you know that I passed the two lowest levels of calculus required for my degree. So you know, I’m something of an expert.
Yeah, we gonna need more rigor on this one.
“A square is a shape made up of four equally long lines a, b, c, d where a is perpendicular to c and d and parallel to b. Each of these lines meet exactly two other lines at it’s ends.”
I’m not a mathematician so there might an odd case somewhere in there. Maybe it has to be confined to a shared plane?
Lines are infinitely long… do you mean line segments?
Wikipedia has a good enough definition: “It has four straight sides of equal length and four equal angles.” Nice and simple.
Pentagon fits that definition also since it doesn’t specify “it has four and only four” sides
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So you’re saying this is the outline of a square in the astral plane? Because it sounds like you’re saying this is a square in the astral plane.
No, just a 2d plane
the angles are interior if you go into the scary world of high level maths and their weird fucking geometries.
this is a square, from a certain point of view
Not if this square is a projection of a curved surface
If it is a projection, then there are more than two curved sides, which also begs credence to the interpretability of the angles they intersect.
Well angles between 3 points are always going to be angles. If your choose a different configuration of dimensional parameters you can effectively project a square from the 2D plane into this exact shape, then logically the angles would follow.
You lost me at 3 points. Could you dumb it down a bit?
Yo bro let’s downscale everything to 2D then upscale it to infinity or something, everything is possible when you project to this demonic crystal justttt this way /s
Hey, that’s my job!
Also I don’t think that’s technically the technical classification. I think that sidedness is an attribute that simply doesnt apply to curves.
You can approximate curves with some number of sides, and the approximation gets more accurate as the number approaches infinity, but it doesn’t actually have the infinite sides.Very cool! I’m always happy to learn something new!
I mean, I’m just pedantic; double check with a mathematician, to be sure lol
I’m genuinely curious, what is your job that requires arithmetic?
I feel like most jobs require arithmetic.
But it is not my career to be a pedant, just my role in life 😜Fair
A square must also have two pairs of parallel sides.
Calculus can find you two pairs of parallel sides, right there on the circle!
No it doesn’t. Right angles + equal length is a sufficient condition
No, it isn’t. A square is a plain, convex and regular quadrilateral with four internal right angles.
In that case, there’s no need to specify anything about the angles. Or, the characterisation the meme is playing with: a shape with four straight sides of equal length and right angles. Adding parallel to the meme’s version doesn’t help.
I’m just tired of this thread. Not only do Lemmy users have this weird urge to show off their high school maths knowledge to dunk on a joke that obviously only works because OP played with the definition, but they’re not even correct. The /r/mathmemes thread was much better.
✌️
That weird urge is like 80% people feeling the need to correct OP’s grammar, like birds do when they hear the wrong birdsong, as if there were anything at stake here.
Honestly, I wish people would play with definitions more. It’s fun. And, unironically, you would be a much better mathematician than most of the know-it-alls here.
I get downvoted for bringing it up, but for fuck’s sake you’re dumping literally everything into this community regardless of the fit. There are a dozen (I’m estimating) other communities that could benefit from the content you post but you have thus far insisted on only posting here.
Can you at least make the tiniest effort to spread content to other communities that would benefit from the increased views and potential subscriptions?
I shall await the fun police and everything’s a meme comments.
At least it’s better than endless American politics.
I’m sure there are more than a dozen and you are right. I’m still trying to get the hang of the whole fediverse thing, but so far most of the more niche communities I have tried to interact with are on different servers not federating with each other? Or maybe I’m doing something wrong? Not sure about that one. Also not sure if cross-posting works. I mean I know it works, but do those posts federate correctly? Can other fediverse apps see them correctly?
I thought your post was funny
The !lemmyshitpost@lemmy.world community fits great for this post.
I thought it was funny, but maybe they have a point? I didn’t even realize I was on the memes community, I just assumed this was on lemmyshitpost. I guess it’s a stretch to call this joke a meme.
Honestly I have no idea what should and shouldn’t be called a meme. In my friend groups this definitely qualifies as a meme, but lemmy is way bigger than my bubble so 🤷.
The best any of us can do is adjust based on feedback I guess.
Thank you for calling it out. Had a look at post history and I agree, blocked. Lemmy is attracting all sorts of random noise lately.
Dumb question but wasn’t there a cross-posting button so you can spread this meme to other communities?
ITT: math people going “listen here you little shit”
If it clucks likes a chicken and scratches like a chicken, it’s Man.
I got that reference!
Behold, a featherless biped!
And for those who don’t: Plato, a Greek philosopher, was putatively asked by a student while teaching at the Academy what the definition of a man (human) was. Plato responded that a man is a “featherless biped”.
Diogenes, another Greek philosopher and infamous quick-wit, caught wind of this and thought that was the dumbest thing ever, so he gate-crashed one of Plato’s lectures and pulled out a chicken which had all of its feathers plucked out and said “Behold, a man!”.
Learned this one in 6th grade geometry: drawing a square in thr corner doesn’t make it 90°
But these are all right angles, as long as the two arcs are centered on the same point as the intersection of the two straight lines.
drawing a square in thr corner doesn’t make it 90°
No, it doesn’t, but it does mean that, for the purposes of your 6th grade geometry question, you can assume the angle is a right angle. Even if it visible looks like 45°, if they put a square there, that’s 90.
More to the point though, a radius of a circle always meets the circumference at 90 degrees. All the squares in this problem are doing is telling you “this line, if it were continued, would be the radius of the incomplete circle”.
Rotate the cone towards you.
Now you see this. 🤯
uhhh, wait. Under what projection is OP’s “square” reduced to an actual square
It’s possible, but there needs to be a thickness in addition to the length and width.
Im gonna need more than that as an explanation. Sandwiches too if you’re making some
Imagine you have a cookie cutter in that shape. Cut a cookie as thick as the chord of the largest arc.
View the new vertical surface of the longest arc that is now a cylindrical section.
Viola, square. 😁
*munches thoughtfully*
this is terrible, but it tastes okay
I’m not a math major, but I always considered it that a square is a special case of rectangle, a rectangle is a special case of parallelogram, and a parallelogram a special case of a quadrilateral, a quadrilateral a special case of a simple polygon.
This shape isn’t a polygon, so it cannot be a square.
Solution:
Explanation:
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in order for the straight lines to be 90 deg with the circles, they must be radii of circles with same central point
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the length of an arc is defined as c = r * θ (where r is the radius, and θ is the angle)
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we define the inner circle with radius r₁ and its arc L₁ = r₁ * θ₁
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we define the outer circle with radius r₂ and its arc L₂ = r₂ * θ₂
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Because of (1), θ₁ + θ₂ = 2π
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To create the shape, L₁ = L₂ = r₂ - r₁
If you start replacing and solving, you will get a 2nd grade quadratic, which has a positive and a negative solution. The positive solution is that magic number.
Why point (5)?
Since the straight lines are radii, they cut the circles at angle θ and 2π - θ, respectively. Adding those, you get 2π.
Okay, but… Why? Is that a theorem that I don’t remember from school?
Take this shape as an example. The “square” in question consists of AC, BD, the outer AB, and the inner CD.
Point (5) means that, since the lines AC and BD are radii of the concentric circles, the arcs AB and CD should have the same inner angle. That’s because the angle COD is equal to AOB.
Since, the inner angle is the same, then the outer AOB should, by definition, be 2π - (the inner AOB), because that’s how radiants work; a circle is 2π rads.
Thank you! But why arc CD and arc AB length should add to 2 PI? Or why does the angle COD times two is 2PI if that’s what you meant?
Point (5) is not about the arcs’ lengths. It’s about the angle they create with the center.
Also, I never said that COD * 2 = 2π. I said (inner COD) + (outer COD) = 2π rads
Thank you, I need an evening with wikipedia to either understand what you wrote or ask more questions, because I don’t see why is that, but now I need to learn/remember that stuff
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Wrong. This is a definition of a [pizza] + [the extra peperoni from the other slices that got stuck to that slice because the cutting was imperfect]
Peperoni are bell peppers. I have no idea why the USA chose to use this word to mean salami, instead of, you know, salami.
You’re thinking of peperoncino, a spiced chilli pepper also known as sweet Italian peppers. We still have salami in the US.
I’d guess pepperoni is called that because it’s dried salami with pepper seasoning.
I found a link just randomly googling. https://www.thoughtco.com/you-say-pepperoni-3972377
Yes, peperoncini are a bit like chili. Peperoni is literally “bell peppers” though. Peperone in singular.
https://dictionary.cambridge.org/dictionary/italian-english/peperone
Pepperoni and salami are totally different dude, you might as well be saying that Americans should just call their potatoes “yams”. And you can get both of those sausages and many, many more on your pizza, often at the same time
Plus the table.
Listen if they put a pepperoni in the center of the pie then a poor cut is clearly the least of our concerns
Always put a pepperoni in the exact middle. It’s like a wishbone, but for pizza. The person who gets the majority of the center pepperoni gets a wish.
A center pepperoni is asking for the center of your pie to be fucked up
