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#1 2010-05-05 20:17:24
- Fruityloop
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What's going on at projectEUREKA?
Problem #1011 at projectEUREKA says:
"If the length of each side of a triangle is increased by 20%, then the area
of the triangle is increased by:"
Take a 3-4-5 triangle, increase each side by 20%
we get 3.6-4.8-6
which has an area of 8.64
8.64/6 = 1.44
I get 44% as the answer, but it says that's wrong.
It even says solution verified.
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#2 2010-05-05 20:28:58
- bobbym
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Re: What's going on at projectEUREKA?
Hi;
They think it is 40%, that is weird, you have done yours right.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#3 2010-05-05 20:43:23
- Fruityloop
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Re: What's going on at projectEUREKA?
Thanks for verifying this BobbyM,
I wasn't sure if I was losing my mind or not.
Help slow global warming. Drive a prius.
July 2012 was the hottest month ever for the U.S.
#4 2010-05-05 20:45:09
- bobbym
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Re: What's going on at projectEUREKA?
You might be, It is just that we are losing it together. I am getting your answer. Is it possible for other than a right triangle that the answer would be 40% ?
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#5 2010-05-06 12:33:48
- bobbym
- Administrator
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Re: What's going on at projectEUREKA?
Hi Fruityloop;
To prove that you are right we can use the general formula for the area of any triangle given 3 points.
A is for any 3 points and B is for those 3 points multiplied by a scaling factor that lengthens each side by 6 / 5. It is easy to see that you can manipulate B to:
C, B is just 36 / 25 times A. That is where the 1.44 = 36 / 25 comes from. You are right for any triangle.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#6 2010-05-07 11:40:43
- Fruityloop
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Re: What's going on at projectEUREKA?
Here's another one: problem #996
A sum of 35 integers is S. Two digits in one of the integers are interchanged and a new sum T is produced. Then the difference S - T is necessarily divisible by:
They think the answer is 11.
Take the sum of the first 35 counting numbers...(35*36)/2 = 630.
Now switch 31 into 13 and add again and you end up with 612.
630-612 = 18 which is divisible by 3 and not 11.
Help slow global warming. Drive a prius.
July 2012 was the hottest month ever for the U.S.
#7 2010-05-07 11:55:03
- bobbym
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Re: What's going on at projectEUREKA?
Hi Fruityloop;
Agreed! I tried it with the series 50 + 51 + 52 + ,,, 84 and switched 81 into 18.
Have you been able to get to their explanations?
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.