Data Sufficiency

VJesus12 wrote:If a triangle has one side of 3 cm and another side of 4 cm, how long is the third side?

(1) The triangle is a right triangle.
(2) The third side is the longest side.

Statement 1:
Case 1: The triangle is 3-4-5
In this case, the third side -- the hypotenuse -- has a length of 5.
Case 2: hypotenuse = 4
In this case, a² + 3² = 4�.
Thus, the length of the third side -- the value of a --- will NOT be 5.
Since the third side can have different lengths, INSUFFICIENT.

Third-side rule:
The length of the third side of a triangle must be LESS THAN THE SUM OF THE LENGTHS of the other two sides and GREATER THAN THE DIFFERENCE BETWEEN THE LENGTHS of the other two sides.

Statement 2:
Applying the third-side rule, we get:
4-3 < third side < 4+3
1 < third side < 7.
It's possible that the third side = 5, making it less than 7 but still the longest side of the triangle.
It's possible that the third side = 6, making it less than 7 but still the longest side of the triangle.
Since the third side can have different lengths, INSUFFICIENT.

Statements combined:
Since the third side must be the longest of the 3 sides, it must serve as the hypotenuse of the right triangle, implying that the triangle is 3-4-5.
Thus, the length of the third side = 5.
SUFFICIENT.

The correct answer is C.