Respuesta :

a = πr^2
441π = πr^2
441 = r^2
21 = r

C = 2rπ
   = 2(21)π
   = 42π cm^2 or 131.88 cm^2

choixongdong
A =  πr^2
r^2 = 441π/π
r^2 = 441
r = 21

C = 2πr
C = 2π(21)
C = 42π

answer
42π cm

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