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October 15th, 2013, 07:21 AM   #1
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Geometrical and Investigative Problem !!! :(

Please Answer with steps for Question 15 in given attachement ! Please
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October 15th, 2013, 09:11 AM   #2
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Re: Geometrical and Investigative Problem !!! :(

WHERE is #15?
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October 15th, 2013, 04:18 PM   #3
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Re: Geometrical and Investigative Problem !!! :(

Quote:
Originally Posted by Denis
WHERE is #15?
You have to scroll down with your cursor on the attachment.
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October 16th, 2013, 04:31 AM   #4
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Re: Geometrical and Investigative Problem !!! :(

Let's make the sides of the square 11 units, so that |AE| = 6 and |BE| = 5. Then the area of quadrilateral BCDE is 88 and the area of triangle CDE is 121/2. Since the median of a triangle divides the triangle into two equal areas (midpoint theorem), the area of triangle CDF is 121/4, so the area of quadrilateral BCFE is 88 - 121/4 = 231/4. Continuing with the midpoint theorem, the area of triangle CDG is 121/8, the area of triangle CDH is 121/16 and the area of triangle CDI is 121/32. Hence area of CDI / area of BCFE = (121/32)/(231/4) = 11/168.
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October 16th, 2013, 06:25 AM   #5
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[attachment=0:2fybxyec]SquareABCD.PNG[/attachment:2fybxyec]
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October 16th, 2013, 11:02 AM   #6
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Re: Geometrical and Investigative Problem !!! :(

Thanks Skip; finally I see the damn thing; Eddy's "scrolling" way no did work for li'l ole me!

Just an observation: why d'heck did the "teacher" not simply say:
point E is on side AB of square ABCD; AE = 6, BE = 5.
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October 17th, 2013, 05:30 PM   #7
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Re: Geometrical and Investigative Problem !!! :(

Quote:
Originally Posted by Denis
why d'heck did the "teacher" not simply say...AE = 6, BE = 5.
Maybe it's because AE=12/11 and BE=10/11.
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October 18th, 2013, 07:14 AM   #8
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Re: Geometrical and Investigative Problem !!! :(

Quote:
Originally Posted by eddybob123
Quote:
Originally Posted by Denis
why d'heck did the "teacher" not simply say...AE = 6, BE = 5.
Maybe it's because AE=12/11 and BE=10/11.
Of course AE=12/11 and BE=10/11, Eddy; BUT you're missing my point.
Above is because 4 was given as area of square, with AE:BE = 6:5.

My point is WHY would the teacher use 4 when 121 could be used
giving SAME results, i.e. 11/168

The point of the problem is not to have the student play with fractions,
(like why 12/11 and 10/11 when 6 and 5 will do same thing?)
but to find a way to end with 11/168 as solution.

Anyway, using Greg's method (thanks for using 6 and 5 Greg!!):
k = side length (11)
a = AE (6)
General case formula:
CDI / BCFE = k / [8(3k - 2a)] ........ = 11/168
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October 22nd, 2013, 02:19 AM   #9
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Re: Geometrical and Investigative Problem !!! :(

For no. 13 see YouTube

http://youtu.be/8NwVsbqrzKE
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October 22nd, 2013, 08:39 AM   #10
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Re: Geometrical and Investigative Problem !!! :(

Quote:
Originally Posted by nubian123
For no. 13 see YouTube
http://youtu.be/8NwVsbqrzKE
The OP did not ask for help on no.13.
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