Respostas

2013-11-21T16:53:12-02:00
D=2*r
18=2*r
r=18/2
r=9

C=2π*r
C=2*3,14*9
C=6,28*9
C=56,52

***Resposta: C=56,52

2013-11-21T16:55:39-02:00
C = 2.3,14 (pi ). 20
6,28 . 20
 = 125,6 ( aachooo kkk )