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Bunuel
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Bunuel
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The average length of the sides of triangle ABC is 12. What is the perimeter of triangle ABC?
Attachment:
22.PNG

This question did not use the word 'approximately'.

(average) = (perimeter)/3;

12 = (perimeter)/3;

(perimeter) = 36.

Answer: E.

P.S. Why should they mention "approximately"?

The correct answer is 36 according to this books.
here, (S+S root 3+2S)/3=12
------> S=7.61
So, S+S root 3+2S=36.01, which is not exactly 36.
did I make any mistake by saying 36 and 36.01 are not the same thing, here?
Should not the writer use the word 'approximately'?
The measurement of this angle is 30-60-90, right? but, if the perimeter is 36, i can say the measurement is not correct; the measurement may be 29-60-90. But, in the figure of this question, it is already said that the two angles is 60 and 90. so, the rest of the angle must be 30, isn't it? if the rest of the angle is 30, then the perimeter must be 36.01, not exactly 36.
Thanks Bunuel for your help.
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Bunuel
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iMyself
Bunuel
iMyself
The average length of the sides of triangle ABC is 12. What is the perimeter of triangle ABC?
Attachment:
22.PNG

This question did not use the word 'approximately'.

(average) = (perimeter)/3;

12 = (perimeter)/3;

(perimeter) = 36.

Answer: E.

P.S. Why should they mention "approximately"?

The correct answer is 36 according to this books.
here, (S+S root 3+2S)/3=12
------> S=7.61
So, S+S root 3+2S=36.01, which is not exactly 36.
did I make any mistake by saying 36 and 36.01 are not the same thing, here?
Should not the writer use the word 'approximately'?
The measurement of this angle is 30-60-90, right? but, if the perimeter is 36, i can say the measurement is not correct; the measurement may be 29-60-90. But, in the figure of this question, it is already said that the two angles is 60 and 90. so, the rest of the angle must be 30, isn't it? if the rest of the angle is 30, then the perimeter must be 36.01, not exactly 36.
Thanks Bunuel for your help.

The point is that S is NOT exactly 7.61 there. It's \(6(3- \sqrt 3)\) and if you substitute this value you'l get exactly 36.

Hope it's clear.
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Bunuel
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Bunuel
iMyself
Bunuel
(average) = (perimeter)/3;

12 = (perimeter)/3;

(perimeter) = 36.

Answer: E.

P.S. Why should they mention "approximately"?

The correct answer is 36 according to this books.
here, (S+S root 3+2S)/3=12
------> S=7.61
So, S+S root 3+2S=36.01, which is not exactly 36.
did I make any mistake by saying 36 and 36.01 are not the same thing, here?
Should not the writer use the word 'approximately'?
The measurement of this angle is 30-60-90, right? but, if the perimeter is 36, i can say the measurement is not correct; the measurement may be 29-60-90. But, in the figure of this question, it is already said that the two angles is 60 and 90. so, the rest of the angle must be 30, isn't it? if the rest of the angle is 30, then the perimeter must be 36.01, not exactly 36.
Thanks Bunuel for your help.

The point is that S is NOT exactly 7.61 there. It's \(6(3- \sqrt 3)\) and if you substitute this value you'l get exactly 36.

Hope it's clear.

Having said that, the method I used is MUCH easier and shorter.
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Bunuel
Bunuel
iMyself

The correct answer is 36 according to this books.
here, (S+S root 3+2S)/3=12
------> S=7.61
So, S+S root 3+2S=36.01, which is not exactly 36.
did I make any mistake by saying 36 and 36.01 are not the same thing, here?
Should not the writer use the word 'approximately'?
The measurement of this angle is 30-60-90, right? but, if the perimeter is 36, i can say the measurement is not correct; the measurement may be 29-60-90. But, in the figure of this question, it is already said that the two angles is 60 and 90. so, the rest of the angle must be 30, isn't it? if the rest of the angle is 30, then the perimeter must be 36.01, not exactly 36.
Thanks Bunuel for your help.

The point is that S is NOT exactly 7.61 there. It's \(6(3- \sqrt 3)\) and if you substitute this value you'l get exactly 36.

Hope it's clear.

Having said that, the method I used is MUCH easier and shorter.
I get it Bunuel. Thank you so much.
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KrishnakumarKA1
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Let the sides be a,b,c.
The average of length = (a + b+ c)/3 = 12
Therefore perimeter = a + b+ c = 12*3 =36
Option E
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