This exercise is asking for the area of a circle with a given circumference. The plan of action is the following:
- Derive the radius from the circumference
- Use the radius to compute the area.
The first step is
[tex] C = 2\pi r \iff r = \dfrac{C}{2\pi} [/tex]
The second step is
[tex] A = \pi r^2 = \pi \dfrac{C^2}{4\pi^2} = \dfrac{C^2}{4\pi} [/tex]
So, the area is
[tex] \dfrac{870^2}{4\pi} = \dfrac{756900}{4\pi} \approx 60232[/tex]
