Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 | 3 | 4 | 5 
6562 posts

Uber Geek
+1 received by user: 528

Trusted

  Reply # 1422050 5-Nov-2015 23:11
Send private message

MadEngineer: It's not a square.

108m^2 is the total area of the whole shape.


Regardless of being a square or not, it's areas is still one side multiplied by the other.

It's shown close to a square in the demo drawing, so not enough to get worked up over.

2391 posts

Uber Geek
+1 received by user: 548

Subscriber

  Reply # 1422083 6-Nov-2015 03:03
Send private message

LennonNZ: long story.. but..

there are 2 answers...
12 and 36

Lets work it out..

Rectangle and Triangle

d(12−0.5d)+2(0.5(0.5d(0.5)d))=108  
−0.25d2+12d−108=0

Use some quadratic formula (a little hard to display here)

d=12 and 36

Of course the image is nothing like that the imaginary shape as the triangle has a negative size or the rectangle does.

(or I got it complete wrong) :-)






The solution of the quadratic equation

d^2 - 48d + 432 = 0

which represents the total area of 108 m2, is:

(d - 36)(d - 12) = 0

and therefore d = 36 or 12.


 
 
 
 


2391 posts

Uber Geek
+1 received by user: 548

Subscriber

  Reply # 1422085 6-Nov-2015 03:33
2 people support this post
Send private message

MadEngineer: I had this question from when I studied NZCE


F*** you Envelope. I never liked letters anyway.

82 posts

Master Geek
+1 received by user: 28


  Reply # 1422155 6-Nov-2015 08:54
3 people support this post
Send private message

And to finish off stating the obvious.  The equation has solutions of d = 12, or d = 36

However you can also determine from the diagram, the constraint of 12 - d/2 > 0.
Using d = 36 gives you a negative result for that equation, therefore d=12 would be the correct answer for this question.


1495 posts

Uber Geek
+1 received by user: 368


  Reply # 1422512 6-Nov-2015 16:32
Send private message

Jaxson:
MadEngineer: It's not a square.

108m^2 is the total area of the whole shape.


Regardless of being a square or not, it's areas is still one side multiplied by the other.

It's shown close to a square in the demo drawing, so not enough to get worked up over.
i added the statement for clarity. Some people get worked up over nothing ...


2926 posts

Uber Geek
+1 received by user: 426

Trusted
Subscriber

  Reply # 1422531 6-Nov-2015 17:12
2 people support this post
Send private message

"That exam wasn't there to test us, it was to trick, no one could of prepared for that," another VCE student wrote.


This student should probably spend a bit more time studying at school, rather than complaining about the content.

438 posts

Ultimate Geek
+1 received by user: 123

Subscriber

  Reply # 1422540 6-Nov-2015 17:42
Send private message

I suspect the envelope problem is a good question that got mangled. If you make the bottom side of the "square" 12-d/4, the d^2 terms cancel and you are left with 12d=108, so d=9. As an added bonus the "square" is now 9x9.75 which is believable for the way it was drawn.

Obviously the total length is now 12+d/4, but it was weird they gave you that redundant info in the first place.

3832 posts

Uber Geek
+1 received by user: 1942

Lifetime subscriber

  Reply # 1422783 7-Nov-2015 11:53
Send private message

andrew027:  which direction bus


I thought that this was a silly question until I saw this:





Suzuki Microbus-like van





Sideface


6 posts

Wannabe Geek
Inactive user


Reply # 1422996 7-Nov-2015 22:41
Send private message

I briefly read the article but then realized it was an Australian 50 cent coin. I think referring to Australian currency really threw the Australian students. After all, how can one make sense of the $2 being smaller than $1, the 20 cents being bigger than both the dollars and the 50 cents being the biggest of all the coins. It defies logic. Now they want students to apply geometry to these illogical manifolds - tough ask! 

1218 posts

Uber Geek
+1 received by user: 511


  Reply # 1423443 9-Nov-2015 08:42
One person supports this post
Send private message

PeerCover: I briefly read the article but then realized it was an Australian 50 cent coin. I think referring to Australian currency really threw the Australian students. After all, how can one make sense of the $2 being smaller than $1, the 20 cents being bigger than both the dollars and the 50 cents being the biggest of all the coins. It defies logic. Now they want students to apply geometry to these illogical manifolds - tough ask! 

But the NZ 50c is bigger than the NZ $1 coin so size is not necessarily relevant.

I was living in Australia when the $2 coin was first issued in 1988 - I remember a nice cartoon of then-treasurer Paul Keating explaining to a reporter that the $2 was smaller than the $1 because two dollars was worth less in 1988 than one dollar was in 1984 (when the $1 coin was released).

And the old joke why a UK 50p coin is shaped the way it is - so you can use a spanner to remove it from a Scotsman's hand.

650 posts

Ultimate Geek
+1 received by user: 132


  Reply # 1423859 9-Nov-2015 16:32
Send private message

andrew027: I still remember from high school geometry (and it has been 38 years since I did high school geometry) that the exterior angles of a polygon add up to 360°. The 50c piece has 12 angles, so 360÷12=30. There are two 50c pieces side-by-side, so the angle at the point the two coins meet is 2×30=60°. For kids who should have learned this stuff within a year or two of sitting the exam, I'm surprised at all the fuss it has created.


I think the fuss reflects the sheer amount of people who did not pay attention during maths class. Fairly basic geometry question.
Personally, I think the question would have been better without multi choice to take away the 'look at the picture and take an educated guess as to what the angle looks like'.

gzt

9386 posts

Uber Geek
+1 received by user: 1359


  Reply # 1423980 9-Nov-2015 20:28
Send private message

8 sided polygon gives a direct answer, but method one was my first choice.

Mad Scientist
17833 posts

Uber Geek
+1 received by user: 2202

Trusted
Lifetime subscriber

  Reply # 1424006 9-Nov-2015 21:30
Send private message

Missus says (the other day) angle of the something something = 360/number of sides of polygon, x2.
wow ... who's the smart one in the family!

ok i can't remember her exact formula ... but sometihng like that. i will ask her again at some stage ..

ok i think that was right. whatever! lol

gzt

9386 posts

Uber Geek
+1 received by user: 1359


  Reply # 1424118 10-Nov-2015 08:28
Send private message

gzt: 8 sided polygon gives a direct answer, but method one was my first choice.

Oh wait I had that confused with a six sided regular polygon. : (.

650 posts

Ultimate Geek
+1 received by user: 132


  Reply # 1424164 10-Nov-2015 09:49
Send private message

joker97: Missus says (the other day) angle of the something something = 360/number of sides of polygon, x2.
wow ... who's the smart one in the family!

ok i can't remember her exact formula ... but sometihng like that. i will ask her again at some stage ..

ok i think that was right. whatever! lol


where n is the number of sides
180-360/n, which can be rearranged to 180x(1-2/n)



1 | 2 | 3 | 4 | 5 
View this topic in a long page with up to 500 replies per page Create new topic



Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Intel reimagines data centre storage with new 3D NAND SSDs
Posted 16-Feb-2018 15:21


Ground-breaking business programme begins in Hamilton
Posted 16-Feb-2018 10:18


Government to continue search for first Chief Technology Officer
Posted 12-Feb-2018 20:30


Time to take Appleā€™s iPad Pro seriously
Posted 12-Feb-2018 16:54


New Fujifilm X-A5 brings selfie features to mirrorless camera
Posted 9-Feb-2018 09:12


D-Link ANZ expands connected smart home with new HD Wi-Fi cameras
Posted 9-Feb-2018 09:01


Dragon Professional for Mac V6: Near perfect dictation
Posted 9-Feb-2018 08:26


OPPO announces R11s with claims to be the picture perfect smartphone
Posted 2-Feb-2018 13:28


Vocus Communications wins a place on the TaaS panel
Posted 26-Jan-2018 15:16


SwipedOn raises $1 million capital
Posted 26-Jan-2018 15:15


Slingshot offers unlimited gigabit fibre for under a ton
Posted 25-Jan-2018 13:51


Spark doubles down on wireless broadband
Posted 24-Jan-2018 15:44


New Zealand's IT industry in 2018 and beyond
Posted 22-Jan-2018 12:50


Introducing your new workplace headache: Gen Z
Posted 22-Jan-2018 12:45


Jucy set to introduce electric campervan fleet
Posted 22-Jan-2018 12:41



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.