Question

Calculati aria discului cu diametru de 8√2

Answer 1

r=8√2:2=4√2
A=πr²=(4√2)²π=32π

Answer 2

$\boxed{A= \pi r^2} \\ r= \frac{D}{2} \\ \Rightarrow r= \frac{8 \sqrt{2} }{2} \\ \Rightarrow r=4 \sqrt{2} \\ A=\pi (4 \sqrt{2} )^2 \\ A=\pi4^2 \cdot2 \\ A= \pi16 \cdot2 \\ \boxed{A=32 \pi}.$