Question Number 188908 by Best1 last updated on 08/Mar/23
$${the}\:{radius}\:{of}\:{a}\:{circle}\:{is}\:\mathrm{12}{cmunits} \\ $$$${find}\:{the}\:{perimeter}\:{of}\:{a}\:{regular}\: \\ $$$${inscribed}\: \\ $$$${a}.\:{triangle} \\ $$$${b}.{heptagon} \\ $$$${c}.\:{decagon} \\ $$
Answered by HeferH last updated on 09/Mar/23
$$\:{P}\:=\:{n}\centerdot{r}\sqrt{\mathrm{2}−\mathrm{2cos}\:\left(\frac{\mathrm{2}\pi}{{n}}\right)} \\ $$$$\:{n}:\:{number}\:{of}\:{sides} \\ $$$$\:{r}:\:{inradius} \\ $$