Using the circumference of a circle formula
In this short you learn how to calculate the circumference.
The circumference is the distance around a circle.
And these are the two formulas you can use to calculate the circumference.
Either we use 2 times pi times the radius or pi times the diameter.
In the first example we are given the radius 3.5 centimeters , so we use the formula two times pi times the radius.
The radius is 3.5
Multiply 2 times 3.5 which is 7. pi times 7 is 7 pi centimeters.
This is approximately 22 centimeters.
In the second example we are given that the diameter is 9 centimeters, so we use the formula pi times the diameter.
So the circumference is equal to pi times the diameter which is 9.
Pi times 9 is 9 pi centimeters.
This is approximately 28.3 centimeters.