Question Number 68930 by Maclaurin Stickker last updated on 17/Sep/19
$$\mathrm{In}\:\mathrm{the}\:\mathrm{figure}\:\mathrm{we}\:\mathrm{have}\:\mathrm{7}\:\mathrm{circles}\:\mathrm{having} \\ $$$$\mathrm{the}\:\mathrm{same}\:\mathrm{radius}.\:\mathrm{Determine}\:\mathrm{the}\:\mathrm{ratio} \\ $$$$\mathrm{between}\:\mathrm{the}\:\mathrm{perimeter}\:\mathrm{of}\:\mathrm{one}\:\mathrm{of}\:\mathrm{the} \\ $$$$\mathrm{circle}\:\mathrm{and}\:\mathrm{the}\:\mathrm{perimeter}\:\mathrm{of}\:\mathrm{the}\:\mathrm{gray}\:\mathrm{region}. \\ $$
Commented by Maclaurin Stickker last updated on 17/Sep/19
Commented by Rasheed.Sindhi last updated on 17/Sep/19
$$\frac{\mathrm{2}\pi\mathrm{r}}{\mathrm{6}}×\mathrm{12}=\mathrm{4}\pi\mathrm{r} \\ $$$$\mathrm{2}\pi\mathrm{r}:\mathrm{4}\pi\mathrm{r}=\mathrm{1}:\mathrm{2} \\ $$
Commented by Maclaurin Stickker last updated on 17/Sep/19
$${Correct}. \\ $$