Answer:
![\large\boxed{C=22\pi y\ ft}](https://tex.z-dn.net/?f=%5Clarge%5Cboxed%7BC%3D22%5Cpi%20y%5C%20ft%7D)
Step-by-step explanation:
The formula of an area of a circle:
![A=\pi r^2](https://tex.z-dn.net/?f=A%3D%5Cpi%20r%5E2)
r - radius
The formula of a circumference of a circle:
![C=2\pi r](https://tex.z-dn.net/?f=C%3D2%5Cpi%20r)
We have the area of a circle
![A=121y^2\pi ft^2](https://tex.z-dn.net/?f=A%3D121y%5E2%5Cpi%20ft%5E2)
Substitute to the formula and solve for r:
<em>divide both sides by π</em>
![r^2=121y^2\to r=\sqrt{121y^2}\\\\r=11y\ ft](https://tex.z-dn.net/?f=r%5E2%3D121y%5E2%5Cto%20r%3D%5Csqrt%7B121y%5E2%7D%5C%5C%5C%5Cr%3D11y%5C%20ft)
Put the value of r to the formula of a circumference:
![C=2\pi(11y)=22y\pi ft](https://tex.z-dn.net/?f=C%3D2%5Cpi%2811y%29%3D22y%5Cpi%20ft)
Answer:
![y=\left|x+1\right|\\y =\left|x-1\right|](https://tex.z-dn.net/?f=y%3D%5Cleft%7Cx%2B1%5Cright%7C%5C%5Cy%20%3D%5Cleft%7Cx-1%5Cright%7C)
You can plug it into a graphing website or calculator to double check
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