tolong sama caranya

Luas = 2.826 cm²
π.r² = 2.826 cm²
3,14 x r² = 2.826
r² = 2.826 : 3,14
r² = 900
r = √900
r = 30 cm

Diameter = 2 x r
                = 2 x 30 cm
                = 60 cm

L =>> π r ^2
2.826 cm2 =>> 3,14 r^2
r^2 =>> √ 2.826 / 3,14
r =>> √ 900
=> 30 cm

d =>> 60 cm