I just received an email from a pair of students. They wrote:
"My friend and I were wondering if we were to represent pi as 22/7 or 3.14."
Since this question can apply to many other problems, I thought that I would share my reply to them. I wrote:
Hi (names removed)
I'm guessing that you are asking this question because a recent problem did specify which representation of pi you should use. However, in the current problem the decision is left up to you.
Does one version seem more or less reasonable to you? Are there other representations for pi that would be more reasonable? What part does accuracy play in this particular problem? How accurate can your final answer be? Don't forget to consider the original measurements given in the problem?
I've probably left you with more to think about, rather than just answering your original question. Just remember that in the end you will have gained a lot more by making this type of decision yourself. Just be sure that your explanation justifies your decision.
Good Luck Judy
I'd love to hear what you say to your students when they ask this very common question.
P.S. I think I'm going to scream if I see one more answer to this problem carried out to 7 or 8 decimal places! ;-)