Math-estimating circumference

Instead of telling the students what the formula was for estimating circumference I had them figure it out themselves.  There were different math stations that each had a circular object.  The students used string to cut the length of the circular object's diameter.  Then they took that string and figured out how many times it would wrap around the object.  The students figured out that for each object the it took the string about 3 times to go around.

Therefore you have to multiply the diameter by 3 to figure out the estimated circumference.  (circumference is finding the perimeter around a circular object)

To find the exact circumference you multiply the diameter by pi.  (pi = 3.14)