Which classification best represents a triangle with side lengths 6 cm, 10 cm, and 12 cm?

The longest side is 12 cm. Compare its square with the sum of the squares of the other sides: 6² + 10² = 36 + 100 = 136, while 12² = 144. Since 136 is less than 144, the triangle is obtuse, so choice C is correct. The sum 6 + 10 > 12 confirms the lengths can form a triangle, but it does not determine whether the triangle is acute or obtuse.

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