To calculate the circumference, you can use the formula:
![C=2\pi r](https://img.qammunity.org/2023/formulas/mathematics/high-school/noytl63lm1q06t23qsdkycir68uwxrmxzb.png)
Where C is the circumference and r is the radius.
Then, you can follow the steps.
1. Substitute the radius in the equation.
In this exercise, r = 40 inches.
![\begin{gathered} C=2\pi40 \\ C=80\pi \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/xg38ysijudayznbuty0eql9qfwice3rxrv.png)
2. To get the approximate result, use π= 3.14 and multiplicate it in the equation.
![\begin{gathered} C=80\cdot3.14 \\ C=251.2in^2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/bctrvmuem9512267sijjw66uxh8glstth0.png)
Done! You found the circumference.
Answer: 251.2 in².