The average length of the sides of triangle ABC is 12. What

[MdAbuAsad]

The average length of the sides of triangle ABC is 12. What is the perimeter of triangle of ABC?
A. 4
B. 6
C. 12
D. 24
E. 36
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.
Ron, 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'?
Is this types of question GMAT standard, Ron?
N.B.: The measurement of this triangle 30-60-90
Source: NOVA

[RonPurewal]

um, what? does the solution actually do that?

say the three side lengths are "x", "y", and "z".
then...
• the AVERAGE of the three side lengths is (x + y + z)/3
• the PERIMETER of the triangle is just (x + y + z)

in other words, if you're given that the average is 12, then the perimeter is just 12 · 3 = 36. huh?

[MdAbuAsad]

um, what? does the solution actually do that?

say the three side lengths are "x", "y", and "z".
then...
• the AVERAGE of the three side lengths is (x + y + z)/3
• the PERIMETER of the triangle is just (x + y + z)

in other words, if you're given that the average is 12, then the perimeter is just 12 • 3 = 36. huh?

Ron, as it is 30-60-90 measurement it has SPECIFIC value, is not it?
here, the smallest side is something, which is opposite of 30 degree, the biggest side is the opposite of 90 degree, and the rest of the side is between smallest and biggest.
Say,
x(S)----->smallest side
Y(S*root 3)------->bigger than smallest side
Z(2S)-------->biggest side of the right triangle

So, {X(S)+Y(S*root 3)+Z(2S)}/3=12
HOW they say that the average of 3 sides is 12? definitely the sides have specific value, isn't it? if we try to find the value of S, then we get S=7.61, which makes the perimeter 36.01.
But, Ron I think there is a problem in the use of root 3. Here I used root 3=1.7321 but this is not the EXACT figure of root 3-there is a little bit different value in original root 3, which is 1.732050807568877…So, I think this calculation gives me wrong figure (e.g., 36.01), am I right Ron?
If yes, then what's your suggestion about the use of Root of something? Should I use the value of root 3 like 1.732050... or not use the value of root 3- i mean JUST use the exact root 3?
Thanks...

[RonPurewal]

nobody said it was a 30º-60º-90º triangle...