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!đ
Submitted â¨â¨2⊠â¨months⊠ago⊠by â¨NONE_dc@lemmy.world⊠to â¨[deleted]âŠ
https://lemmy.world/pictrs/image/f418776a-2517-4e60-a68f-9bc4bc11bb74.png
Comments
Coskii@lemmy.blahaj.zone â¨2⊠â¨months⊠ago
CaptainBasculin@lemmy.ml â¨2⊠â¨months⊠ago
Fun fact: In Turkeyâs 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 â¨2⊠â¨months⊠ago
all angles have to be absolutely accurate
To what tolerance, though? Writing math exams has now become an engineering problem.
SchmidtGenetics@lemmy.world â¨2⊠â¨months⊠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 lessonâŚ
Coskii@lemmy.blahaj.zone â¨2⊠â¨months⊠ago
I donât 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 â¨2⊠â¨months⊠ago
And whatâs 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 â¨2⊠â¨months⊠ago
Then they could use decimals so itâs unlikely to get it right without calculating, 60.17°, 40.29°, 35.43°
explodicle@sh.itjust.works â¨2⊠â¨months⊠ago
If the student eventually does geometry for money, theyâll discover that customer CAD files invariably have some bizarre error like this.
nul9o9@lemmy.world â¨2⊠â¨months⊠ago
I was scared I forgot basic trig stuff.
wieson@feddit.org â¨2⊠â¨months⊠ago
Itâs 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 â¨2⊠â¨months⊠ago
Thatâs based on the assumption that the two angles in the middle add up to 180, which canât be assumed by inspection alone as demonstrated by the visibly square 80° angle
surewhynotlem@lemmy.world â¨2⊠â¨months⊠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 â¨2⊠â¨months⊠ago
Nice one, forgot this was an option too. You are missing a set of brackets though ;)
BlueMagma@sh.itjust.works â¨2⊠â¨months⊠ago
I love that every comment focus on the math puzzle. Since the other stuff is clearly uninteresting.
bjoern_tantau@swg-empire.de â¨2⊠â¨months⊠ago
135° for anyone wondering.
expatriado@lemmy.world â¨2⊠â¨months⊠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 â¨2⊠â¨months⊠ago
What a bunch of bullshit. Just draw it way off 90 if you donât want people to use a protractor. I calculated 125° because of this (but Iâm happy I still got the right wrong answer, if that makes sense)
SendMePhotos@lemmy.world â¨2⊠â¨months⊠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 â¨2⊠â¨months⊠ago
Enkers@sh.itjust.works â¨2⊠â¨months⊠ago
Iâd get out my red pen and write: âBad diagram. -1pt See me after class.â
slaacaa@lemmy.world â¨2⊠â¨months⊠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 âsplitâ the space over a straight line).
Image
stebo02@lemmy.dbzer0.com â¨2⊠â¨months⊠ago
you mean to say the right angles arenât right angles? disgusting, get this outta my sight
Maalus@lemmy.world â¨2⊠â¨months⊠ago
Nope. The value is âundefinedâ. You donât 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 isnât a datum saying the bottom âlineâ is straight, nor does it say the triangle on the right is an isosceles triangle, it is impossible to solve.
gedaliyah@lemmy.world â¨2⊠â¨months⊠ago
I donât see any indication that this is limited to the Euclidean plane either
bjoern_tantau@swg-empire.de â¨2⊠â¨months⊠ago
Image
Enkers@sh.itjust.works â¨2⊠â¨months⊠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, itâd be better to put a hash through them both to indicate theyâre parallel, especially given the deceptively drawn most-likely-not-a-right-angle.
lugal@sopuli.xyz â¨2⊠â¨months⊠ago
For context: it used to be 675° a few years back so the math checks out.
expatriado@lemmy.world â¨2⊠â¨months⊠ago
thatâs not how global warming works
ThisIsAManWhoKnowsHowToGling@lemmy.dbzer0.com â¨2⊠â¨months⊠ago
I got 125.
180-(90-35)=x 180-55=x 125=x
LotrOrc@lemmy.world â¨2⊠â¨months⊠ago
How assuming it is a right angle Nothing stays that it is
erin@lemmy.blahaj.zone â¨2⊠â¨months⊠ago
It isnât 90 degrees because the image is misleading. 60+40+y=180. y=80