Pi Are Round

The beautiful young woman is our friend, Grace.  She comes to stay with us from time to time.  And we benefit from her friendship, her delicious cooking, and her prayers for us.  This is a picture from her last visit when she made us apple pie.  It was the only picture of a pie that I have, so. . .  But I am sure you will hear more about Grace in the future as she is coming in two week for another visit.  So I am glad to introduce you to her now.

Jor Man asked at breakfast, "What is Pi?"  He had heard of it in a movie, and then again in a book he is reading.

I got out a sheet of paper and began to explain, "Imagine we were putting in a garden, and we wanted to make it a circle.  How would be know how much fence to buy to go around the outside?"

"Well,"  Jor Man reasoned, "How big is the circle?"  He already knew about radius and diameter, so we went over these terms with the girls.  Then we added the term "circumference" to all their vocabularies.

The magic of Pi was revealed.  Big Dad showed them how the circumference of any circle is the diameter three times and a little more.  That's true whether it's a really big house-sized circle, or an itty-bitty circle.  Ooohh!  Aaaahh!  The kids, including the very-hard-to-impress Jor Man, were wowed!

Next I "Swagbucks" searched the term Pi, and read it to them to the 20th digit.  We explained that it goes on forever and never repeats!  More awe.  I also told them that my brother had Pi memorized to the hundreth digit when we were kids.  Really.

We did the math to figure out how big the fence would need to be for our imaginary garden.  Then I asked, how much area is inside the circle?  Huh?

I explained.  Let's say we want to plant wildflowers, and the package says to sprinkle so much seed per square foot of garden.  Confused looks.  An explanation of the concept of a square foot ensued.  Then we went back to the question.  How many square feet in our imaginary garden circle?  How could we find out?  We drew a square around the circle and used the diameter as the length of the sides.  We estimated the number of square feet in the circle based on the square feet in the square.

Then I showed them how to use Pi to figure the area of a circle.  Pi x radius squared, or Pi r squared.  (Forgive my not using the symbols here.  I fear they will not translate well in the blog and come out all funky.)

Pi r square.  "No!"  Jor Man laughed.  "Pi are round!"  And I laughed, too.  Because that was what my mother said when she taught it to me.    We figured out the area and compared it to our estimate.  It's a good thing we have Pi.  The estimate was pretty off.

Wish you were here!