Bantuin yaa no 19 pakai cara, makasih

L = phi.r.r
346,5 = 22/7.r²
r² = 346,5 * 7/22 = 110,25
r = 10,5

kell= phi.d
      = 22/7. 21
      = 66 m

66 : 3 = 22 batang (C)