You should be able to solve this

you should be able to solve this

Other urls found in this thread:

bhavinionline.com/2017/08/brainteaser-find-height-red-bar-picture/
twitter.com/SFWRedditGifs

3 ft

12m

8m?

11m?

8m

8m

6.75 m?

6.67

show your work

I cheated and used reverse image search but the only answer I can find states the 4m on the wall would be 6m if on the ground but doesn't explain how they come to that.

Can someone spell this out for a retard?

It's just ratios

if the red stick was 4m tall the shadow would be just 6m long and not on the wall. any vertical addition to the shadow is 1:1. so 4+4m

No

Shadows on surfaces parallel to the casting object in question always show real height. so you add the four meters on the wall to the 6*(2/3) meters from the ground to get 8.

8m. I think this logic more or less makes sense.

Thanks user, good explanation.

this

>8m. I think this logic more or less makes sense.
Yep, is 8 exactly, the 6m on the floor are equally to 4m in height plus the other 4m gives you 8.

sounds about right

We're not told that the shadow is on a 90 degree angle. Unsolvable. Does Sup Forums even math?

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Why don't you ask your teacher for help or go bother /sci with your homework instead?

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kek

it is 8m.

its all about triangles, actually.

> The top of the green box is darker than the front face.
> That means the light source cannot be higher than 2m.
> At most it can be at 2m
> Implying it would cast an infinitely long shadow.
> impossible situation.

Nice try mathfag.

no it's not

Absolute madman

Spoiler solution: pretend the shadow on the wall has it's own shadow in the same direction to create an imaginary full ground shadow. 2:3 = 4:x. X= 6m. Ground shadow length of 6m plus further 6m of imaginary shadow is a full ground shadow of 12m. 2:3 = y:12. Y= 8m. The red tower is exactly 8m

Out of fucking nowhere.
Thousand keks.

ya it is. and extrapolation.

0

You don't seem to understand how light works.

The green tower has a 2:3 ratio with its shadow. It is two meters and its shadow is 3.

Count the 4 meter shadow as another tower, if it would have continued on the ground it would have 2:3 ratio which would be 4:6

so total on the ground would have been 12 feet of shadow behind the red tower, which means the red tower would be 8:12 which follows the 2:3 ratio

I would say 8m. Btw where are you op?

Thats about 3 green blocks high.

up your butt and around the corner, faggot

round 2 class

About tree fiddy

8m

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b

lol math faggots love their trick questions to rack up crosses on tests

>hurr hurr, you didn't consider this user

anything above basic level maths is for cucks

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(2/3 = x/6) + 4

b - 12

It's obviously A.

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You're not taking in account your perspective. More light would be reflecting towards your eyes off a surface facing both you and the light source. The top of the bar, depending on the reflectivity and texture of the surface, would point more light in the opposite direction, away from your eye, making it appear darker.

Assuming the light source is infinitely far away, 8m. Otherwise unsolvable.

What about the light reflected off the ground surface. It would light up the front but not the top. Adding to the direct light would make the front brighter than the top.

The answer is 8 meter. It comes from the assumption the light source is infinitely far away, otherwise not enough information is provided

Assuming alpha is the angle of light source vs horizon:
tan(alpha) = 2/3 = (x-4)/6
implies x = 8.

15. If a 2m casts a 3m shadow then 6m casts 9 and 4m casts 6. 9+6

Right, so thats why the green one is important. For the green tower to be casting a shadow downwards, the the light would have to be *above* it. Since the side facing right is the same color as the top, we can conclude the light is not above it. Thus, impossible.

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8 meters. The difference of the shadow’s length for the 2 boxes is 10m-3m=7m. The real image projects a shadow that’s 1 meter greater, therefore the shadow difference of 7m will add a real height of 7m-1m=6m. 6m+2m=8m.

8m. faggots

100000

this

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>boxes
None of these people understand how shadows work.

I looked up the answer to this and I'm not satisfied with the explanation

bhavinionline.com/2017/08/brainteaser-find-height-red-bar-picture/

the answer assumes that the shadow on the wall is 1:1 with the height of the bars, with no explanation of why it assumes that (no mention of the angle of the light source to the bars).

But that is not a safe assumption, since we all know you can make a shadow on a wall either taller or shorter than the object casting the shadow based on the angle of the light source

according to the website where the image comes from they got the answer correct

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Approximately
11.150521555565259752231848431163m

see idiot.

with no other info, you assume 1:1 in that situation

shadows, how do they work?

but you do have other info, you can see that the shadow on the ground casts a shadow of a 3:2 ratio to the height of the bar

with this information I believe you can calculate the angle of the light source to the bars

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6, ya'll niggas don't even BODMAS.

You don't even need that actually.

All you have to do is calculate the length of the hypotenuse of the right triangle formed by the smaller block and it's shadow, then calculate the angle between the hypotenuse and the smallest side.

Basically you need to figure out the angle at which the light is hitting the blocks.
Once you have that, you can use trigonometry to figure out the rest.

>I'm the user who posted btw

>american education

Did I get it wrong? My math is a bit rusty so I could have fucked it up somewhere.

right, this is similar to how I was trying to solve it, but instead of using trig I tried to use logic, and I guess I got the wrong answer. I figured the light source was at about a 30 degree angle to be casting that shadow, but your way is better

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IT IS YA BOI TYRONE IN THE MUTHA FUCKIN THREAD THAT RED DICK IS FUCKIN 688Y4543ERGU7543Emm WIDE NIGGA. MY WORD IS LAW BITCH

this

it depends also upon the distance from the light source, this can be solved assuming the light source is far enough away that the difference between the angles of the light source and the two stacks is negligible.

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tan(theta)=2/3

height=(tan(theta)*x)+y = ((2/3)*6)+4= 4+4= 8

Note: is me

Everyone saying 8m does not understand how shadows works. There is not enough information to determine the height of the red bar. While 8m is a valid answer, it is not the correct answer as there an infinite number of valid answers between [4m, 8m]. See the image i made for proof.

OP posted a really shitty question.

The guy who posted gets it, as well as . for the explanation on the website is incorrect. and see this post

what is the correct answer if you assume the shadow is being cast by sunlight?

12ft and 3 7/16 decimeters

EDIT: Made a mistake. There are actually infinite answers between 2m and 8m. See the updated picture.

It wouldn't fit the scenario cuz the sun is moving the entire time, in the diagram the sun would need to be 33.7 degrees above the horizon. That only happens for one instant. And the sun is not a point light source, so the shadows would not be solidly defined. Looking aside those two issues, using the sun at 33.7 degrees the height would be closer to 8m.

this guy also gets it

holy fuck dude, you have completely gone beyond the wording of the question, no one gives a fuck how shadows work or the infinite fractions of shadow length thrown by the sun. I'm no math fag, but your supposed to use the information IN THE QUESTION to find the answer..it looks like some level of trig to me but yea, fuck math

so much this

>I'm technically right and that's the best type of right.
What if there is a diffuse light source and the shadows are actually black paint? What if there aren't any shadows and this is actually a flat illustration meant only to serve to ask a theoretical question and is neither to scale nor accurately colored? The possibilities are endless.

It's a shitty question, anontard. the information IN THE QUESTION *is not enough* to find the answer. You don't need trig to realize this. It's basic geometry.

Put your hand in front of a light and move it back and forth, you'll understand.

What information are you missing? The correct way to handle it is to give the answer in terms of the missing data.

doesn't change the fact that it's a shitty question, and the explanation on the website is wrong.

It should state "assume the light source is a point an infinite distance away".

>give the answer in terms of the missing data.
Most of the faggots in this thread saying "8m" aren't doing this. That means they don't understand the question.

17 1/2 cubits.

>It should state "assume the light source is a point an infinite distance away".

No it doesn't. You can calculate the height as a function of the distance to the light source if you want to be a pedantic cunt

But the answer and explanation on the website doesn't do this, user. Same with half the people in this thread. They just assumes the light source is an infinite distance away without stating it, and concludes the answer is 8m. That demonstrates a poor understanding of how shadows work.

>That demonstrates a poor understanding of how shadows work.
You are demonstrating a poor understanding of how questions work.

You’re an idiot, tan is opposite over adjacent, the fuck you diving by hypothnuse for?

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