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geekhack Community => Off Topic => Topic started by: tp4tissue on Sat, 12 December 2020, 18:40:01
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ROUND 3, This one is a Classic. It is a square, All outward endpoints are Midpoints, the numbers are areas. excuse the crudeness of Tp4's drawing, did it wit creditcard
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ROUND 2: find the shaded area,
[attach=2]
in Elementary school ?
-translation:
"Must know elementary school problem.
Find the area of the shaded section."
Full-disclosure, Tp4 doesn't even remember the geometry rules to solve this.
[attach=1]
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okay so the full length lines cut it exactly in half. The upper right has an area totally 11, the upper left total 13. If the question area is exactly 1/4th, it should be 1/3rd of the overall total of 18 -- which is 6.
The left + right, equal 12, and should be half. The top, plus 6 again, equals twelve to match.
The answer is 6.
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That doesn't sound right, but I have no idea. Maybe I've assumed it's harder than it is.
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It is a triangle... solved.
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The answer is 4 or 8, ust go counter clockwise.
Why you guys gotta make it so difficult?
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The answer is 4 or 8, ust go counter clockwise.
Why you guys gotta make it so difficult?
(https://i.imgur.com/ucmvQmZ.gif)
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Had to ask a guy, parently it's quite ez. No trig rules, jus'algebra.
Spoiler ALERT
b1h1=7
b2h1=6
b2h2=5
b1h2=x
Divide, h1, h2 drops out, you get 7*5/6 = x
Tp4 kept trying to add it all together, and had stupid large expansions, (probably solvable). But Duhhmmmmm....
Man, too rusty..
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I don't like that answer tp4 - firstly because it's decimal (what are the chances three are whole numbers and one isn't? Would surely have taken a long time to find that scenario and why bother) and second because it makes no sense (it would spoil the spoiler to say more, so I wont) That said the way they teach English here makes no sense (phonics - the alphabet isn't a b c it's ah bu cu, and qu and ch are 'letters') so who knows, maybe this is 'right' too.
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I've been seeing this style of question going around the interwebs for... literally two decades now. They are always 'Chinese elementary school questions' and I am wondering if this is really some long running propaganda campaign. Because my kids are in elementary school, and they don't hit this kind of thing.
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I don't like that answer tp4 - firstly because it's decimal (what are the chances three are whole numbers and one isn't? Would surely have taken a long time to find that scenario and why bother) and second because it makes no sense (it would spoil the spoiler to say more, so I wont) That said the way they teach English here makes no sense (phonics - the alphabet isn't a b c it's ah bu cu, and qu and ch are 'letters') so who knows, maybe this is 'right' too.
It's a trade off.
/Proud Chinez parents: "Dis' why all our kiz come out messed up, but economically secure"
(https://i.imgur.com/zkdP3qz.gif)
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I've been seeing this style of question going around the interwebs for... literally two decades now. They are always 'Chinese elementary school questions' and I am wondering if this is really some long running propaganda campaign. Because my kids are in elementary school, and they don't hit this kind of thing.
In China they also have different -Lvls- of schools.
The rural schools are slower, because some of the students have to work the field or help out at home, making tofu/noodles/fermented goods.
Then they have the Tier-1-City schools, where it's Cram school EVERYDAY from Elementary through Highsko. These souls Never get to play Arena-Of-Valor (greatest Moba of all time)..
If you look at the college entrance exams, it's nothing like the SATs over here, It's like all the AP exams put together, but significantly harder and more problem types.
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I've been seeing this style of question going around the interwebs for... literally two decades now. They are always 'Chinese elementary school questions' and I am wondering if this is really some long running propaganda campaign. Because my kids are in elementary school, and they don't hit this kind of thing.
In China they also have different -Lvls- of schools.
The rural schools are slower, because some of the students have to work the field or help out at home, making tofu/noodles/fermented goods.
Then they have the Tier-1-City schools, where it's Cram school EVERYDAY from Elementary through Highsko. These souls Never get to play Arena-Of-Valor (greatest Moba of all time)..
If you look at the college entrance exams, it's nothing like the SATs over here, It's like all the AP exams put together, but significantly harder and more problem types.
Let's just say that I have a fair bit more first hand, local knowledge than most about the elementary schooling system out in this part of the world. I'm certainly paying enough !@#$ money for it.
Oh, and I went through for several decades hearing about these "SAT" things, and when I finally saw what they were it was like some kind of joke. It's a weird schooling system over there, with this AP stuff making up for how silly the SAT is. I mean, I am pretty crap at maths... but those SAT things where a real WTF moment.
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My first thought is that there isn't enough information. Usually problems like this state a few givens, like "This is a square" or "These two sides are equal in length" or "This angle is 90 degrees" or "These lines are perpendicular/parallel."
But this doesn't look like a square since the lines aren't parallel and the areas of the opposite triangles are different, which means I can't assume any of the angles is 90 degrees. The only thing I do know for sure is the top angle of the shaded triangle is congruent to the bottom angle of the 6 unit triangle.
I don't know how to find the base or height of the known triangles because knowing the area leaves me with two variables (A=1/2bh -> 6=1/2bh -> 12bh).
I don't think the spoiler solution is correct because measuring the shape on my screen shows that none of the sides is equal to another, so it's just a quadrilateral, meaning there are four bases, not two.
I generally suck at math, so everything I said could be bunk.
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@kavik, I am 100% confident the posted solution is correct.
More Spoiler
The reason it works is because these triangles share the centered bases and heights
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Update , Round 2..
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That one's much easier, there's a right angle.
Spoiler:
big triangle is double classic 3, 4, 5, small one is 1.33x so the 'square' is 5.33x6=32
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EDIT: Sorry, wrong math. I thought the picture describes area and not the length of the sides.
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ROUND 2: find the shaded area,
(Attachment Link)
OLD________________________________________________________
in Elementary school ?
-translation:
"Must know elementary school problem.
Find the area of the shaded section."
Full-disclosure, Tp4 doesn't even remember the geometry rules to solve this.
(Attachment Link)
I failed grade 10 math do you expect me to do this question
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ROUND 1
35/6
hint:
what tp did, triangles have shared bases and heights
use elimination method to express the area in question by the areas given
ROUND 2
32
hint:
use the Strahlensatz
Had to ask a guy
be the guy
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ROUND 3 !!