Final answer:
The perimeter of the polygon is 600,000 km. The length of the missing side is 240,000 km.
Step-by-step explanation:
The perimeter of the polygon can be found by adding up the lengths of all the sides. In the given solution, the lengths of the sides are provided: 200,000 km, 100,000 km, and 300,000 km. So, the perimeter is calculated by adding these lengths together: 200,000 km + 100,000 km + 300,000 km = 600,000 km.
To find the length of the missing side, we subtract the lengths of the known sides from the perimeter. In this case, the known sides have lengths of 100,000 km and 200,000 km. So, the length of the missing side is calculated by subtracting these lengths from the perimeter: 600,000 km - (100,000 km + 200,000 km) = 240,000 km.
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