Solve 2pir72^circ/360=2r^2-3

$$\frac{ 2 \pi r72 ^ { \circ } }{ 360 } = 2 { r }^{ 2 } -3$$

Solve for r_72

$$r_{72}=-\frac{180\left(3-2r^{2}\right)}{\pi }$$

Steps for Solving Linear Equation

Multiply both sides of the equation by 360.

$$2\pi r_{72}=720r^{2}-1080$$

Divide both sides by 2\pi .

$$\frac{2\pi r_{72}}{2\pi }=\frac{720r^{2}-1080}{2\pi }$$

Dividing by 2\pi undoes the multiplication by 2\pi .

$$r_{72}=\frac{720r^{2}-1080}{2\pi }$$

Divide 720r^{2}-1080 by 2\pi .

$$r_{72}=\frac{180\left(2r^{2}-3\right)}{\pi }$$

Solve for r

$$r=\frac{\sqrt{10\left(\pi r_{72}+540\right)}}{60}$$

$$r=-\frac{\sqrt{10\left(\pi r_{72}+540\right)}}{60}\text{, }r_{72}\geq -\frac{540}{\pi }$$