Answer:
28 km
Step-by-step explanation:
One leg = 35 km
Second leg = 21 km
We need to find the length of the missing leg. Using Pythagoras theorem, we can find it.
Hypotenuse² = base² + perpendicular²
[tex]x=\sqrt{35^{2}-21^{2}}\\\\x=28\ km[/tex]
So, the length of the missing leg is equal to 28 km.