Activity
Pi from circles
Measure circumference and diameter, divide one by the other, and you have π. Try with a real bowl and string!
60 cm
Diameter
120 cm
Circumference
376.99 cm
Circumference ÷ Diameter
3.141593
That ratio is the same for every circle, no matter how big or small. We call it π.
Pick any circle. Measure its circumference. Measure its diameter. Divide. You always get the same number — about 3.14159… — no matter how big or small the circle is. That number is π.
Try it with a real bowl, plate or wheel and a piece of string. Wrap the string around (circumference), measure across (diameter), divide. You'll be surprised how close you get.