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.
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.
Jan 31, 2005
|This is assuming planar geometry... but yeah, fair call. |
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).
May 28, 2005
|Um, I didn't think that there was enough info in that to get that answer (0).|
Oct 21, 2005
|i kinda got it, but i feel just so stupid today, i don't thinki could get any of them!! |
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.|
Nov 11, 2005
|SO EASY, SO ELEMENTARY,|
Nov 29, 2005
|I couldn't get it...the "open calcualtor" tricked me (sort of) |
Dec 01, 2005
|Good teaser. |
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. |
Jan 22, 2006
|That was easy, but it might be harder for some1 who didn't know that rule.|
Jan 27, 2006
|I liked this one, thanks great teaser|
Feb 24, 2006
Mar 12, 2006
|Thats really clever|
Mar 27, 2006
|I got this one....but I do think it goes in the Trick section.....|
Apr 02, 2006
|very easy.. i got it right.. |
Apr 07, 2006
|i cant believe i missed that! |
Jun 19, 2006
|first angle =0|
second angle =0
third angle = 180.
There is a triangle, and its area is zero.
Jul 03, 2006
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.
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.|
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
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.
Feb 15, 2007
Jun 26, 2007
|Um, no. Pythagoras would have nothing to do with this one! |
Fun quiz, almost got me!
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. |
Jul 23, 2007
|I looked that up, btw, to make sure there weren't any rules about triangles it was breaking |
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 NON-COLINEAR points. That means they can't all be on the same point, so it's not a triangle.
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. |
Back to Top