# Think Kilometers

## Work Time

# Think Kilometers

There is also a rule about lightning and thunder that works for kilometers rather than miles: *The distance of lightning in kilometers is the time between the appearance of the lightning and the sound of the thunder in seconds, divided by 3.*

Think about this rule and consider the following question:

- If there are 7 sec between the lightning and the sound of thunder, how far away is the lightning in kilometers?
- Follow the problem-solving process:
- Understand the situation.
- Represent the situation.
- Answer questions about the situation.
- Check that your answer makes sense.

VIDEO: Lightning and Thunder

## Hint:

- Use the problem-solving process to help guide your thinking.
- What is the independent variable in the problem situation? What is the dependent variable? How can you represent these variables on your graph?
- How can you use a ratio table to help you make your graph?
- What intervals and scale will you use for your graph?
- Include the units for all quantities—in calculations, graphs, tables, and so on—to help you make sense of the values.