Question

calculati aria discului cu diametrul de 8 m

Answer 1

$A_{disc}=\pi r^{2}$

d=2r=>$r=\frac{d}{2}$

d=8m=>$r=\frac{8m}{2}=4m$

$A_{disc}=4^{2}\pi=\boxed{16\pi m^{2}}$

Daca vrei:
$\pi=~3,14$

$A_{disc}=16*3,14m^{2}=\boxed{50,24m^{2}}$