Respostas

2014-04-29T11:35:50-03:00
C = 2.π.r
280 = 2.π.r
2.π.r = 280
r = 280/ 2.π
r = 140/π
2014-04-29T11:38:17-03:00
C=2r \pi
280=2r \pi
r= 280/2*3,14
r= 280/ 6,28
r= 44,58 (aproximadamente)