Math/Geometry problem! Anyone recognise this?
Math/Geometry problem! Anyone recognise this?
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AdvocatusD

Original Poster:

2,278 posts

260 months

Friday 21st August 2009
quotequote all
My uncle and I are currently engaged in a battle of IQ one-upsmanship!

He has just said to remind him to show me "a truly baffling conundrum" (involving squares and rectangles) at dinner next week.

I've asked for a hint to what it is (so that I can rely on the internet's IQ to come across as having worked it out on the spot myself! wink) and he's come back with this.

"Ooh, wouldn't you like to know... OK, it's about how the area of a square can be different from the area of a rectangle even though the parts which make up the square are identical to those which make up the rectangle."

Anyone on here recognise this problem? Even better who's got the solution to let me look like a complete genius!? biggrin

My only idea thus far, is more of a reasoning than an "answer" (if there even is one!) is:

If memory serves me right, I would assume it's because a rectangle is a quadrilateral and parallelogram, while a square is not just a quadrilateral and a parallelogram (like the rectangle), but also rhombus as well?

I guess the inter-relationship means, the maths somehow goes funny! It’s quite amazing these problems maths can post.


Edited by AdvocatusD on Friday 21st August 14:11

ewenm

28,506 posts

274 months

Friday 21st August 2009
quotequote all
If a square is chopped up and made into a rectangle using all the bits, then the total areas will be the same. If it's only the total length of the edges that is preserved then you can get different areas.

Need the precise question to say how the maths works.

Edited by ewenm on Friday 21st August 13:49

djmck30

258 posts

215 months

Friday 21st August 2009
quotequote all
AdvocatusD said:
My uncle and I are currently engaged in a battle of IQ one-upsmanship!

He has just said to remind him to show me "a truly baffling conundrum" (involving squares and rectangles) at dinner next week.

I've asked for a hint to what it is (so that I can rely on the internet's IQ to come across as having worked it out on the spot myself! wink) and he's come back with this.

"Ooh, wouldn't you like to know... OK, it's about how the area of a square can be different from the area of a rectangle even though the parts which make up the square are identical to those which make up the rectangle."

Anyone on here recognise this problem? Even better who's got the solution to let me look like a complete genius!? biggrin

My only idea thus far, is more of a reasoning than an "answer" (if there even is one!) is:

If memory serves me right, I would assume it's because a rectangle is a quadrilateral and parallelogram, while a square is not just a quadrilateral and a parallelogram (like the rectangle), but also rhombus as well?

I guess the inter-relationship means, the math somehow goes funny! It’s quite amazing these problems math can post.
It might be something along these lines:

http://en.wikipedia.org/wiki/Missing_square_puzzle

Also it's Maths, by the way wink

voyds9

8,490 posts

312 months

Friday 21st August 2009
quotequote all
I remember this being on the TV. A square is cut into bits and reassembled as triangle with one less area how can this be, answer there are small gaps between the pieces of the triangle which add up to missing area.

http://en.wikipedia.org/wiki/Missing_square_puzzle

Edited by voyds9 on Friday 21st August 13:54

Graham E

13,018 posts

215 months

Friday 21st August 2009
quotequote all
"the parts" might be matchsticks or similar, so the lngths of the sides are different, hence different area?

Eg square 4 x 4 vs rectangle 3*5.
4*4 = 16.
3*5 = 15.

But, it's probably better than that, otherwise he's assuming you;re not very good at gcse maths =)

Parsnip

3,262 posts

217 months

Friday 21st August 2009
quotequote all
Two things i would ask, if by the same, does he mean the perimeters are the same? If so, obviously, the areas can be different. If you have 100 1mm long sticks, you can make a several different rectangles, the one with the largest area being the square.

If you have 4 sticks of equal length, the only way to make different areas would be to move two of the sticks close to make a rectangle:

|---|
| |
|---|

-|-|-
| |
-|-|-

I reckon the fomatting will get fooked, but you get the point.

I may not be thinking laterally enough however, depends what sort of puzzle it is.

AdvocatusD

Original Poster:

2,278 posts

260 months

Friday 21st August 2009
quotequote all
Goddamn typos in the subject lines! banghead Apologies, I actually did go to school, even a rather good college!

I'm afraid this is all the information we can hope to get gents! Asking anything more will raise suspicions. We want him to *think* I fight fair right? biggrin

mrmr96

13,736 posts

233 months

Friday 21st August 2009
quotequote all
AdvocatusD said:
My uncle and I are currently engaged in a battle of IQ one-upsmanship!

He has just said to remind him to show me "a truly baffling conundrum" (involving squares and rectangles) at dinner next week.

I've asked for a hint to what it is (so that I can rely on the internet's IQ to come across as having worked it out on the spot myself! wink) and he's come back with this.

"Ooh, wouldn't you like to know... OK, it's about how the area of a square can be different from the area of a rectangle even though the parts which make up the square are identical to those which make up the rectangle."

Anyone on here recognise this problem? Even better who's got the solution to let me look like a complete genius!? biggrin

My only idea thus far, is more of a reasoning than an "answer" (if there even is one!) is:

If memory serves me right, I would assume it's because a rectangle is a quadrilateral and parallelogram, while a square is not just a quadrilateral and a parallelogram (like the rectangle), but also rhombus as well?

I guess the inter-relationship means, the math somehow goes funny! It’s quite amazing these problems math can post.
This one "xii. Square And Rectangle " from this page: http://www.puzzle.dse.nl/math/index_us.html
There's also a load more on there you can stump him with. I particularly like "x. Traveling Bird" from the same page.

HTH

Please report back after your Dinner with your Uncle and let us know how you got on!!

AdvocatusD

Original Poster:

2,278 posts

260 months

Tuesday 1st September 2009
quotequote all
mrmr96 said:
[Please report back after your Dinner with your Uncle and let us know how you got on!!
mrmr96 thanks for that, spot on with the answer!

Uncle dearest is rather deflated. It wasn't just me at dinner it turned out, so when he broke out the question, I had quick look at it along with everyone else, pronounced my inability to crack it and then let everyone talk about it till the cows came home.

Uncle said he had the answer, wasn't suprised no-one could get it, but would give everyone till the end of dinner before he divulged the answer.

Unsuprisingly, no-one had the answer, so come the end of dinner one of the guests asked to be told the answer (clearly, it was KILLING him!). My uncle then looked around the table with an expression that sort of said "so, you all admit defeat eh?" and was about to tell us what the answer was, when I chipped in with a very humble "actually, I may have an idea if you want to hear it..." Uncle looked at me and sort of handed me the paper so that I could look at it, but I waved it away with a casual, "Oh no, it's cool, I looked at it in the beginning. If I'm right it's quite a simple solution, shall I go ahead?"

I proceeded to blow him out the water with a careful analysis of the problem and how it could only be solved one way! He looked rather staggered as did the rather attractive daughter of one the guests wink (who, I should add was sitting next to my fiancee)!

The whole thing, the timing, the guests, the solution and the (out of character) self depracation from yours truly has had me pissing myself for a week! It was worth its weight in gold!

stuthemong

2,532 posts

246 months

Tuesday 1st September 2009
quotequote all
AdvocatusD said:
mrmr96 said:
[Please report back after your Dinner with your Uncle and let us know how you got on!!
mrmr96 thanks for that, spot on with the answer!

Uncle dearest is rather deflated. It wasn't just me at dinner it turned out, so when he broke out the question, I had quick look at it along with everyone else, pronounced my inability to crack it and then let everyone talk about it till the cows came home.

Uncle said he had the answer, wasn't suprised no-one could get it, but would give everyone till the end of dinner before he divulged the answer.

Unsuprisingly, no-one had the answer, so come the end of dinner one of the guests asked to be told the answer (clearly, it was KILLING him!). My uncle then looked around the table with an expression that sort of said "so, you all admit defeat eh?" and was about to tell us what the answer was, when I chipped in with a very humble "actually, I may have an idea if you want to hear it..." Uncle looked at me and sort of handed me the paper so that I could look at it, but I waved it away with a casual, "Oh no, it's cool, I looked at it in the beginning. If I'm right it's quite a simple solution, shall I go ahead?"

I proceeded to blow him out the water with a careful analysis of the problem and how it could only be solved one way! He looked rather staggered as did the rather attractive daughter of one the guests wink (who, I should add was sitting next to my fiancee)!

The whole thing, the timing, the guests, the solution and the (out of character) self depracation from yours truly has had me pissing myself for a week! It was worth its weight in gold!
Hang on. If being good at maths impresses pretty girls, how come I was like 32 before I had my first kiss?

RDE

5,037 posts

243 months

Tuesday 1st September 2009
quotequote all
mrmr96 said:
I particularly like "x. Traveling Bird" from the same page.
Thanks, that made me feel really clever as I got it in about 20 seconds, while thinking "That's probably too simplistic".

mrmr96

13,736 posts

233 months

Tuesday 1st September 2009
quotequote all
AdvocatusD said:
mrmr96 said:
[Please report back after your Dinner with your Uncle and let us know how you got on!!
mrmr96 thanks for that, spot on with the answer!

Uncle dearest is rather deflated. It wasn't just me at dinner it turned out, so when he broke out the question, I had quick look at it along with everyone else, pronounced my inability to crack it and then let everyone talk about it till the cows came home.

Uncle said he had the answer, wasn't suprised no-one could get it, but would give everyone till the end of dinner before he divulged the answer.

Unsuprisingly, no-one had the answer, so come the end of dinner one of the guests asked to be told the answer (clearly, it was KILLING him!). My uncle then looked around the table with an expression that sort of said "so, you all admit defeat eh?" and was about to tell us what the answer was, when I chipped in with a very humble "actually, I may have an idea if you want to hear it..." Uncle looked at me and sort of handed me the paper so that I could look at it, but I waved it away with a casual, "Oh no, it's cool, I looked at it in the beginning. If I'm right it's quite a simple solution, shall I go ahead?"

I proceeded to blow him out the water with a careful analysis of the problem and how it could only be solved one way! He looked rather staggered as did the rather attractive daughter of one the guests wink (who, I should add was sitting next to my fiancee)!

The whole thing, the timing, the guests, the solution and the (out of character) self depracation from yours truly has had me pissing myself for a week! It was worth its weight in gold!
Awesome!!!! Wish I'd been there to see his (and her!) face!! Good work chap.