Solution: The area of the triangle is $ \frac{1}{2} \times 9 \times 12 = 54 $ km². The altitudes corresponding to each side are $ \frac{2 \times 54}{9} = 12 $, $ \frac{2 \times 54}{12} = 9 $, and $ \frac{2 \times 54}{15} = 7.2 $. The shortest altitude is $ 7.2 $ km, or $ \frac{36}{5} $. Thus, the length is $\boxed{\dfrac{36}{5}}$ km.

Mon, 04 May 2026 13:42:23 +0000

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