I hated pictures like this in school. The numbers are just slapped on an inaccurate image and somehow they expect people to ignore the obvious right triangles and just focus on the math part of it.
To the center of the earth!📉
Submitted 1 month ago by NONE_dc@lemmy.world to [deleted]
https://lemmy.world/pictrs/image/f418776a-2517-4e60-a68f-9bc4bc11bb74.png
Comments
Coskii@lemmy.blahaj.zone 1 month ago
CaptainBasculin@lemmy.ml 1 month ago
Fun fact: In Turkey’s university admittance exam, all angles have to be absolutely accurate, and measurements have to be scaled down perfectly to the visible shape in a geometry question.
Enkers@sh.itjust.works 1 month ago
all angles have to be absolutely accurate
To what tolerance, though? Writing math exams has now become an engineering problem.
SchmidtGenetics@lemmy.world 1 month ago
If it was to scale you could just use a protractor and skip the whole math part, which is the entire part of the lesson…
Coskii@lemmy.blahaj.zone 1 month ago
I don’t see that as a downside as long as these two questions are also included.
How many degrees make up the inner angles of a triangle?
How many degrees make up one side of a straight line?
Pacattack57@lemmy.world 1 month ago
And what’s wrong with that. Utilizing real world solutions to problems is a life skill. Not some obscure formula that you will forget anyway.
elxeno@lemm.ee 1 month ago
Then they could use decimals so it’s unlikely to get it right without calculating, 60.17°, 40.29°, 35.43°
explodicle@sh.itjust.works 1 month ago
If the student eventually does geometry for money, they’ll discover that customer CAD files invariably have some bizarre error like this.
nul9o9@lemmy.world 1 month ago
I was scared I forgot basic trig stuff.
wieson@feddit.org 1 month ago
It’s even easier than going the triangle route.
A four-corner shape always has 360° internally.
So the internal angle of corner X is 360-(60+40+35).
The exterior angle therefore is 360-360-(60+40+35) = 60+40+35 = 135
brown567@sh.itjust.works 1 month ago
That’s based on the assumption that the two angles in the middle add up to 180, which can’t be assumed by inspection alone as demonstrated by the visibly square 80° angle
surewhynotlem@lemmy.world 1 month ago
No, you should completely ignore the bottom half of the center line. You end up with a shape with four turns. Those four internal angles always add to 360.
anonymouse@sh.itjust.works 1 month ago
Nice one, forgot this was an option too. You are missing a set of brackets though ;)
BlueMagma@sh.itjust.works 1 month ago
I love that every comment focus on the math puzzle. Since the other stuff is clearly uninteresting.
bjoern_tantau@swg-empire.de 1 month ago
135° for anyone wondering.
expatriado@lemmy.world 1 month ago
correct, just commening the 100/80 intersection looks like 90/90, i think it was intentionally misleading, classic trying to get you problem
Worx@lemmynsfw.com 1 month ago
What a bunch of bullshit. Just draw it way off 90 if you don’t want people to use a protractor. I calculated 125° because of this (but I’m happy I still got the right wrong answer, if that makes sense)
SendMePhotos@lemmy.world 1 month ago
Yes I originally thought 90 but then noticed the absence of a right angle sign. Also 60+40=100 which means the last angle should be 80. Making that perpendicular 100/80
AcesFullOfKings@feddit.uk 1 month ago
Enkers@sh.itjust.works 1 month ago
I’d get out my red pen and write: “Bad diagram. -1pt See me after class.”
slaacaa@lemmy.world 1 month ago
Yes, simple doodle below for anyone wondering. You start from left, and calculate them 1 by 1, based on the angles that you already know. It is quite simple actually, you just have to know they always add up to 180 (within triangle, and when you “split” the space over a straight line).
Image
stebo02@lemmy.dbzer0.com 1 month ago
you mean to say the right angles aren’t right angles? disgusting, get this outta my sight
Maalus@lemmy.world 1 month ago
Nope. The value is “undefined”. You don’t have enough info to arrive at 135 - you are assuming that the bottom angle (sum of the angles that touch) is 180 degrees. Since there isn’t a datum saying the bottom “line” is straight, nor does it say the triangle on the right is an isosceles triangle, it is impossible to solve.
gedaliyah@lemmy.world 1 month ago
I don’t see any indication that this is limited to the Euclidean plane either
bjoern_tantau@swg-empire.de 1 month ago
Image
Enkers@sh.itjust.works 1 month ago
I think assuming 2 line segments which make up a larger straight line segment to be parallel is generally accepted practice, and that would trump the angles that are drawn inaccurately.
Of course, it’d be better to put a hash through them both to indicate they’re parallel, especially given the deceptively drawn most-likely-not-a-right-angle.
lugal@sopuli.xyz 1 month ago
For context: it used to be 675° a few years back so the math checks out.
expatriado@lemmy.world 1 month ago
that’s not how global warming works
ThisIsAManWhoKnowsHowToGling@lemmy.dbzer0.com 1 month ago
I got 125.
180-(90-35)=x 180-55=x 125=x
LotrOrc@lemmy.world 1 month ago
How assuming it is a right angle Nothing stays that it is
erin@lemmy.blahaj.zone 1 month ago
It isn’t 90 degrees because the image is misleading. 60+40+y=180. y=80