Question

calcule a medida da área dr do circulo cujo raio e 4 cm. use : r=3,14

Answer 1

$\mathbf{Dados:}\\\\ \mathrm{r=4\ cm}\\ \mathrm{\pi\approx3,14}\\\\ \textbf{Resolu\c{c}\~ao:}\\\\ \mathrm{A=\pi r^2\ \to\ A=3,14.4^2}\\\\ \mathrm{A=3,14.16\ \to\ \boxed{\mathbf{A=50,24\ cm^2}}}$