MHB Help Me Find the Perimeter of Tn+1

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The discussion revolves around calculating the perimeter of a sequence of triangles, starting with T1, which has sides 2011, 2012, and 2013. The sequence is defined such that Tn+1 has side lengths determined by the points of tangency of the incircle of triangle ABC. The perimeter of the final triangle in the sequence is stated to be 1509/28, although there are some calculations leading to different values, including 1509/128. The triangle inequality rule is highlighted as a crucial factor in determining the validity of the triangle's existence in the sequence. Ultimately, the correct perimeter is confirmed to be 1509/128.
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Could I get some help please?Let T1 be a triangle with sides 2011, 2012, and 2013. For n > = 1, if Tn = triangle ABC
and D, E, and F are the points of tangency of the incircle of triangle ABC to the
sides AB, BC, and AC, respectively, then Tn+1 is a triangle with side lengths
AD, BE, and CF, if it exists. What is the perimeter of the last triangle in the
sequence (Tn) ?

The answer is 1509/28.

Please do not laugh at my solution.

6036/2 , 6036/4 ,6036/8 ... 6036/4096.
I put 4096 as the last term because the next one is 8192

My answer 6036/4098 = 1509/1024
 
Last edited:
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veronica1999 said:
Could I get some help please?Let T1 be a triangle with sides 2011, 2012, and 2013. For n > = 1, if Tn = triangle ABC
and D, E, and F are the points of tangency of the incircle of triangle ABC to the
sides AB, BC, and AC, respectively, then Tn+1 is a triangle with side lengths
AD, BE, and CF, if it exists. What is the perimeter of the last triangle in the
sequence (Tn) ?

The answer is 1509/128.

Please do not laugh at my solution.

6036/2 , 6036/4 ,6036/8 ... 6036/4096.
I put 4096 as the last term because the next one is 8192

My answer 6036/4098 = 1509/1024

The stopping condition is where the longest of \(AD\), \(BE\), \(CF\) for \(T_n\) is greater than the sum of the other two.

So do you know the relationship between the sides of consecutive triangles in the sequence?CB
 
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Thanks!

I see I forgot to consider the triangle inequality rule.

6036/512 = 11.787

11.787/3 = 3.92

2.92 3.92 4.926036/1024 = 5.89

5.89/3 = 2.96

0.96 1.96 2.96
 
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Oops it was my mistake. I meant 1509/128. Sorry.
 
veronica1999 said:
Oops it was my mistake. I meant 1509/128. Sorry.

Which is what I get.

CB
 
Last edited:
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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