Question 551748
Is it possible for a triangle to have side lengths of 19 cm, 13 cm , and 7 cm? why?
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Yes, it is.
Why not?
Here are the angles in degrees.
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cos(A) =	-143/182 A =	141.7867893
cos(B) =	241/266	 B =	25.0396596
cos(C) =	481/494	 C =	13.17355111
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The other tutor pointed out that 19^2 <> the sum of 7^2 + 13^2.  That means it's not a right triangle.
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The longest side, 19, has to be less than the sum of the other 2, which it is.
The shortest side, 7, has to be more than the difference of the other 2, which it is.
So it's valid for a triangle.
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If you can find the angles as I did, it's proof of validity.