Hmmm, its done me!
http://sharkinfested.custard.org/triangle.gif

<thud>

quite simple, its a very clever optical illusion. look at the pictures carefully, the angle of the top line on the green and red triangles are diferent, so on the lower of the two images you get a kink in the top line, its not straight! Not easy to see. :D

Your threshold for pain is obviously much higher than mine, John! :D

It's a tallent i have. :D LOL

I am very good at that kind of thing, just the way my mind works. :o Does my brothers head in, he brought home a similar style of puzle no one at work could work out after hours of study, took me 50 seconds. :D LOL

But both lines start at the same place?

I'm with John on this one :D worked it out for myself, just a little slower, and not read his post and gone "oh yeah" :D:D:D

:cool:

All done with ropes and pullies

hmm looking closer i see whta you mean :/

Doc, the angle of the slope on the two triangles is different. On the top, the angled lines bends inwards, on the bottom, it bends outwards, hence the differences.

:cool:

this was on not so long back !! bloody triangles !!

Just in case i wasn't clear;

The first time i saw it here, it amused me for quite a while, and i thought the answer was very interesting.

The second time i saw it here, i did look at the lines again, just to be sure it was the same puzzle, and waited for someone else to post the answer.

The third time i saw it here, i thought "Here we go again", and posted SIAL or something similar.

The fourth time i saw it here, SIAL was, well, too SIAL, so i left it to others to take the barracking!

The fifth time i saw it here, i thought the poster was having a laugh. But they weren't.

The sixth time i saw it here, lots of new people quickly came on, apparently never having seen it before, so i played along, and edited my posts which gave the answer too quickly, apparently.

And here i am, posting bollox on airing number seven!!!

:)

Angle of red triangle to horizontal = tan-1(3/8) = 20.6 degrees
Angle of green triangle tohorizontal = tan-1(2/5) = 21.8 degrees

so the long edge has a bend of 1.2 degrees in it!

I would have have used the Search bar to avoid the obvious SIAL comments but didnt have time to scour through the thousands of posts :p I needed the answer quickly to look good elsewhere on the t`internet :D

just do the maths to calculate the angle and you will see they are diferent. tan(A) = opposite/adjacent, tan(A) = adjacent/oposite.

Red has 90, 20.55 and 69.44 degree angles (180 total)
Green has 90, 21.80 and 68.19 degree angles (180 total)

damn, took to long to find my calculator LOL

:D

LOL @ Telboy! ;)

I was thinking exactly the same thing!