### May 21, 1997

Construct an ellipse and, given amount of angle traversed in a month, calculate
the length of a year using Kepler's second law. In other words, divide the
planet's natural "year" into twelve equally long "months".

For next time: think about these questions:

1. What tools did you need to do this problem?

2. Which of these tools do you think Kepler had?

3. How do you think Kepler would have done the problem?

4. What do you suppose gave him the idea for his second law?

5. Why did Kepler's second law stick?

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