Răspuns:
Explicație pas cu pas:
5a)2*π*r = 44*π | :π
2r = diam=44
b) 2*π*r = 12*π | :π
2r = 12
c) 2*π*r = 7*π | :π
2r = 7
6a) π*r^2 = 64*π | :π
r^2 = 64 = 8^2
r =8
lungimea = 2πr = 2π*8 = 16*π
b) π*r^2 = 121*π | :π
r^2 = 121 = 11^2
r =11
lungimea = 2πr = 2π*11 = 22*π
c) π*r^2 = 20*π | :π
r^2 = 20
r = V20 = V(4*5) = 2V5
lungimea = 2πr = 2π*2V5= 4V5*π
