Work out 90% of 7000 km

1. Understand the problem: We need to calculate $90\%$ of $7000 \text{ km}$.

2. Convert the percentage to a decimal: The percentage $90\%$ can be written as a decimal by dividing by $100$:
$$90\% = \frac{90}{100} = 0.9$$

3. Perform the multiplication: Multiply the decimal by the given value:
$$0.9 \times 7000$$

4. Calculate the result:
$$0.9 \times 7000 = 9 \times 700 = 6300$$

Thus, $90\%$ of $7000 \text{ km}$ is $6300 \text{ km}$.