#1  
Old 07-12-2002, 03:28 PM
Spider Spider is offline
Guest
 
Join Date: Jul 2000
Posts: 147
stupid math puzzle thingy

I've looked at it. I've added it up. Hell, I even drew it, cut it out and tried to figure it out. But I'm too dumb.

Where the hell does the space come from?

Please help me because I can't sleep until someone tells me how obvious the answer is and how dumb I am.

(and if this is one of those "what rhymes with purple?" type questions which people try pulling please smack me now)
Advertisements  
  #2  
Old 07-12-2002, 03:47 PM
Robot Arm Robot Arm is offline
Guest
 
Join Date: Jun 2000
Location: Medford, MA
Posts: 21,099
The top figure is not a perfect triangle, the diagonal bends very slightly inward. It's hard to tell on a computer monitor, and the thickness of the lines probably disguises it even more. If you make another piece that represents the full triangle, 13 by 5 units, and draw the diagonal very precisely, then lay your existing pieces on it, you should see a thin sliver that's missing. When you rearrange the pieces for the bottom figure, and switch the blue and red triangles, the triangle bends slightly outward, just enough for one square unit.

If you prefer a math approach, the area for the full triangle (13 by 5) should be 32.5 square units. Total up all of the pieces and it's only 32 square units. You can also find that the slopes of the blue and red triangles aren't the same.
  #3  
Old 07-12-2002, 03:59 PM
Spider Spider is offline
Guest
 
Join Date: Jul 2000
Posts: 147
That is the most annoying thing in the world. Do you know how long I spent dealing with that? I added up the area a million times, and thought that I was just missing something! (well, apparently I was!)

I wasn't kidding when I said I made cutouts.

All that for a stupid optical illusion/trick.

"oh I could while away the hours, conferrin' with the flowers
Consultin' with the rain.
And my head I'd be scratchin' while
my thoughts were busy hatchin'
If I only had a..."
  #4  
Old 07-12-2002, 04:22 PM
Eats_Crayons Eats_Crayons is offline
Guest
 
Join Date: May 2000
Location: Bye old school Dopers.
Posts: 5,801
Quote:
Originally posted by Robot Arm
The top figure is not a perfect triangle, the diagonal bends very slightly inward.
Agreed. Look carefully at how the outline of the triangles meet the lines of the grid as I've circled them here and you can compare them a little easier. Look soon because I'm not keeping the image up for two terribly long lest it be a puzzle spoiler for everyone.
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:44 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2017 Sun-Times Media, LLC.

 
Copyright © 2017