Explicație pas cu pas:
..
L =2pi R
8cm
L=2pi ×8=16 pi cm
b,) 2 radical 3
L= 2 pi ×2 radical 3= 4 pi radical 3 cm
c) 3,5 cm
L= 2 pi ×3=7pi cm
d) 3radical 5 supra 2
L= 2pi ×3 radical 5 supra 2 = 3pi radical 5 cm
