The missing side in the given triangle is x = √193 km
The Pythagoras theorem is expressed as;
x^2 = a^2 + b^2
where
x is the longest side
Substitute the given side
x^2 = 12^2 + 7^2
x^2 = 144 + 49
x = √193 km
Hence the missing side in the given triangle is x = √193 km
Learn more on Pythagoras theorem here; https://brainly.com/question/654982
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