S кр = пR^2 С = 2пR =2x3 xR =6R 1/4C = 10.2дм C = 10.2x4=40.8дм
6R = 40.8
R = 5.1 дм S кр =2пх5,1^2 = 2х3х26,01= 156 дм2
S кр = пR^2 С = 2пR =2x3 xR =6R 1/4C = 10.2дм C = 10.2x4=40.8дм
6R = 40.8
R = 5.1 дм S кр =2пх5,1^2 = 2х3х26,01= 156 дм2