Given:
a.) A circle has a radius of 20 cm.
b.) It has a central angle that measures 216 degrees.
Let's draw the figure to better understand the scenario:
For us to be able to determine the arc length, we will be using the following formula:
![\text{ Arc Length = }(\Theta)/(360\degree)2\pi r](https://img.qammunity.org/2023/formulas/mathematics/college/nz1wqd905pz0tsuqyp1lgywghveejq4btq.png)
Where,
r = radius of the circle
Θ = central angle
We get,
![\text{ Arc Length = }(216\degree)/(360\degree)2\pi(20)](https://img.qammunity.org/2023/formulas/mathematics/college/sd9gb1weclm2jx74noe042pn4rf9nhylr8.png)
![\text{ = }(3)/(5)\text{ \lparen40}\pi)](https://img.qammunity.org/2023/formulas/mathematics/college/nfox5i27zqgsyik217rc902l6jyit80zkp.png)
![\text{ = }(120)/(5)\pi](https://img.qammunity.org/2023/formulas/mathematics/college/skz5zlczmjxy7nlvdmz12mobs4dhalgumg.png)
![\text{ Arc Length = 24}\pi\text{ cm or 24\lparen3.14\rparen = 75.36 cm}](https://img.qammunity.org/2023/formulas/mathematics/college/k808ph3xyrjngqs6l1z9hssgyng1vei4lh.png)
Therefore, the length of the arc is 24π cm or 75.36 cm