Question

Va rog mult de tot!!​

Answer 1

Lc=2pi×r

9pi=2×3,14×r

9×3,14=6,28r

28,26=6,28r

r=4,5

Acerc= pi×r²

8 pi=pi×r²

8×3,14=3,14×r²

=>

r²=(8×3,14):3,14

r²=25,12:3,14

r²=8

$r = \sqrt{8} \\ r = 2 \sqrt{2}$