Area of a Triangle
Math brain teasers require computations to solve.
What is the area of a triangle with sides 1, 3, and 4 inches?
HintYou don`t need a formula to figure this out.
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Answer
It`s impossible to have a triangle with those sides. The sum of two of the sides is equal to the third side. The result would be a straight line, and the area would be zero.
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Comments
Atropus
Jan 31, 2005
 This is assuming planar geometry... but yeah, fair call. 
Sane
Feb 17, 2005
 I don't understand why it is not possible?
Check out my plane sketch.
It is 3.3, but rotate the 1 inch line a bit and it would be 3.0 (MS Paint it difficult to manage line lenghts).
http://img220.exs.cx/img220/9486/plane2zn.png 
darthforman
May 28, 2005
 Um, I didn't think that there was enough info in that to get that answer (0).
Oh, well.

converse_chik
Oct 21, 2005
 i kinda got it, but i feel just so stupid today, i don't thinki could get any of them!! 
stephiesd
Nov 04, 2005
 technically, there is a formula involved. you need to know that 2 sides can't equal the third, and this should probably go in the trick section. 
myrtha
Nov 11, 2005
 SO EASY, SO ELEMENTARY,
VERGOGNA 
dude7
Nov 29, 2005
 I couldn't get it...the "open calcualtor" tricked me (sort of) 
hidentreasure
Dec 01, 2005
 Good teaser. 
musicmaker21113
Jan 11, 2006
 Good one. I really had to think about this one, as to why it can't work. BTW, Stephanie's comment that there is a formula involved is not true. You don't need any formula at all, just visualization.
Good job! 
Celanba
Jan 22, 2006
 That was easy, but it might be harder for some1 who didn't know that rule. 
SPUTNIK2
Jan 27, 2006
 I liked this one, thanks great teaser 
fezface
Feb 24, 2006
 SMARTY PANTS! 
Methlos
Mar 12, 2006
 Thats really clever 
TehIgnored
Mar 27, 2006
 I got this one....but I do think it goes in the Trick section.....
very clever 
brainjuice
Apr 02, 2006
 very easy.. i got it right.. 
spazzyjazzy93
Apr 07, 2006
 i cant believe i missed that! 
udoboy
Jun 19, 2006
 first angle =0
second angle =0
third angle = 180.
There is a triangle, and its area is zero. 
banzai
Jul 03, 2006
 thanks. 
Qrystal
Jul 20, 2006
 Ahhhhh nooooo this one got me, I can't believe it!
I actually worked through a bunch of things... might've 'accidentally' ignored some negative signs under square roots, and got 3.35 sq in somehow... then I looked at the hint, got puzzled, didn't bother to rethink it....
bleh. I'd better go give my math minor back or something. 
rrn0rrnrrnY
Sep 03, 2006
 This is not a math teaser. It is a trick teaser with math as the subject. Could have been in question form and used for teaser. 
Dishhead5
Sep 17, 2006
 cant believe i missed that...
i was thinking of the cosine rule:
a^2 = b^2 + c^2  2bc cos A
and then once u get angle... well then u use area = (1/2)ab sin C
well yeah thats what i thought 
Trickster1992
Jan 19, 2007
 [technically, there is a formula involved. you need to know that 2 sides can't equal the third, and this should probably go in the trick section.]
There is no formula involved. Somebody already pointed out you don't need formula, you just need your mind's eye.. 2 sides actually can equal the 3rd side. It's called the pythagorean theorum. 
piebob222
Feb 15, 2007
 easy 
mosca
Jun 26, 2007
 Um, no. Pythagoras would have nothing to do with this one!
Fun quiz, almost got me! 
leftclick
Jul 23, 2007
 An interesting one. I think this triangle [180deg, 0deg, 0deg] fits all the basic rules about triangles  it consists of three points in a plane, the internal angles add up to 180deg, the external angles add up to 360deg, and each external angle is equal to the two opposite internal angles. So the answer should be zero, and it's not a trick. 
leftclick
Jul 23, 2007
 I looked that up, btw, to make sure there weren't any rules about triangles it was breaking 
javaguru
Jan 16, 2009
 I reread it just to make sure since I read the numbers correctly since it was immediately obvious it wasn't a triangle. Definitely belongs in the trick category.
And to leftclick: a triangle is defined by three NONCOLINEAR points. That means they can't all be on the same point, so it's not a triangle. 
javaguru
Jan 16, 2009
 Uh, mistyped: not only can't they all be on the same point, they can't all be on the same line either. 
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