Tolong ya yang di linkerin ya guys

a. r =21 cm
K =  2 × π × r
= 2 × 22/7 ×21 =132 cm
L =  π × r²
= 22/7 × 21²
= 1386 cm²
b. r = 30 cm
K = 2 ×π × r
= 2 × 3,14 ×30
=188,4 cm
L = π × r²
= 3,14 × 30²
=2826 cm²
c. r = 49 cm
K= 2 ×π × r
= 2 × 22/7 × 49
= 308 cm
L = π × r²
= 22/7 × 49²
= 7546 cm²