|
|
|
Excursion 6: Meeting Pi This week, we’re going to discover an intriguing number. This number is an irrational number, which means if you write it as a decimal, the number never ends, and never repeats. So we can never write it down exactly. In upcoming excursions, we’re going to tell you some interesting stories about how this number had been calculated in history, but first, let’s meet it. The number is called Pi, a Greek letter, written like this: P . First, a bit of a detour, but as all the detours at Newton’s Window, a detour with a purpose. Make a chart with six rows, 3 columns. In the first column write "circumference," in the second, write "diameter," and in the third, write "ratio." It’s fine if you don’t know what these mean; you don’t need to now. Find six different round objects – for example, a plate, a cup, a can, a clock, a saucer, a tire. Take your first object, and measure it around its circumference, that is, around the outside edge. Write this number in the circumference column. Then, for that object, measure the distance straight across the middle (or center.) Write this number in the diameter column. Do the same for all six objects. Now the fun! Dividing. Divide the circumference by the diameter, making sure to use the right one for each, don’t mix them up!. Try to divide without a calculator, if you’ve learned how to divide. Write it as a decimal, accurate to several decimal places. Look at your numbers. What do you see? Are they close to each other? Stay tuned. We have some neat things to tell you about this number. ~~~~~~~~~~~~~~~~~ Answer to Excursion # 5: Deception. Last week’s excursion didn’t give you a specific problem, but asked you to hunt for ads that try to take advantage f people’s fear of math in order to trick them into spending more money than they’d like. Keep looking, and send us any you find, and we’ll post them here. The more you understand math, the less likely you’ll be deceived. Here’s one example. People often confuse per cent OFF, and per cent OF. Sometimes an ad will have 10% written really large, and the "OFF" will be written quite large. Here’s the difference: Suppose something costs $80.00. If something cost only 10% OF its original price of $80.00, it would only cost $8.00. But if it cost 10% OFF of the original price, that would mean the $8 would be subtracted from the $80.00, leaving $72.00. Better than $80, but not nearly as big a drop as $8.00 would be. Usually, when percentages are given in ads, it means OFF, not OF. Keep on the lookout for more deceptive ads, and send them to us. |
|
Great Math
Treasure Hunt Raising Test Scores Free Newsletter Beyond Homework Help Gifts that Teach Web: http://www.NewtonsWindow.com Email Us
|
