When would you want to find the circumference of a circle?

The first step to calculate circumference of a circle is to know the formula. There are two formulas that can be used for the purpose. They are:

• Circumference of a circle formula 1: C = π x diameter
• Circumference of a circle formula 2: C = π x 2 radius

Here are a few illustrations that would make problem solving related to finding the circumference of a circle easy:

Using the Radius:

If the value of the radius is known then it can be put in the 'circumference of a circle equation' already mentioned and the value calculated. For example:

Given that the radius of circle is 3 cm.

Circumference of the circle: C= π x 2 radius

or, C= 3.14 x 2 (3) cm

or, C= 18.84 cm

Using the Diameter:

If the value of the diameter is known it can be directly put in the 'circumference of a circle equation' and the circumference calculated. For example:

Given that the diameter of a circle is 6 cm.

Circumference of the circle: C= π x diameter

or, C= 3.14 x 6 cm

or, C= 18.84 cm