We want to estimate the radius of this circle given the circumference. The circumference C of a circle with radius r is calculated using the formula below.
C=2Ï€ r
From the figure, we know that the circumference of the circle is 8.9mm. We can substitute 8.9 for C in the formula and then calculate r. We will use 3.14 as an estimate for π.
Are you interested in learning more about circles? Our Mathleaks original content can teach you all about them! Check out the following resources to see real-world uses for circumference and area, how circles compare to other shapes and why, as well as some higher level topics that you can look forward to learning about in Geometry and Algebra 2.
