/sci/ - Science & Math

>>14642087
Gee anon, pay attention.
You use the cosine rule, you get [math]2 \pi R = 2 \pi \dfrac{7}{\sqrt{2 - \sqrt{2}}}[/math]
Attempt to rationalize the denominator by multiplying by [math]\dfrac{ \sqrt{2 - \sqrt{2}} }{ \sqrt{2 - \sqrt{2}} }[/math] for [math]2 \pi \dfrac{7 \sqrt{2 - \sqrt{2}} }{ 2 - \sqrt{2} }[/math]. Attempt to rationalize again by multiplying by [math]\dfrac{2 + \sqrt{2} }{ 2 + \sqrt{2} }[/math] and you'll get the thing you posted.