Ariel's work is not correct for determining whether the triangle with side lengths 9, 15, and 12 forms a right triangle. The Pythagorean Theorem states that for a triangle to be a right triangle, the square of the length of the longest side (the hypotenuse) should be equal to the sum of the squares of the lengths of the other two sides.
In this case:
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Identify the longest side. The side lengths are 9, 15, and 12. Here, 15 is the longest side.
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Apply the Pythagorean Theorem, which states: \[ c^2 = a^2 + b^2 \] where \(c\) is the longest side. Thus: \[ 15^2 = 9^2 + 12^2 \]
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Calculate the squares: \[ 15^2 = 225 \] \[ 9^2 = 81 \] \[ 12^2 = 144 \]
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Add the squares of the other two sides: \[ 81 + 144 = 225 \]
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Compare: \[ 225 = 225 \]
Since both sides of the equation are equal, this means that the triangle with sides 9, 15, and 12 does form a right triangle.
Therefore, the correct response is, "Yes, Ariel's work is correct and this is a right triangle." Ariel's conclusion is incorrect because she did not correctly identify and separate the longest side in her calculations.