mohon bantuan nya dari no 9 sampai 19

9) K = 62,8
phi= 3,14
K = phi. d
62,8 = 3,14 . d
d = 62,8÷ 3,14
= 20
r = d÷ 2 = 20÷2 = 10 (c)
10) A
11) K=37,68
K = phi. d
37,68 = 3,14 . d
d = 37,68÷ 3,14
= 12
r = 6
L ling = phi.r.r
= 3,14.6.6 =113,04 (c)
13) L ling besar = phi.r.r
= 3,14 .10.10
= 314 ÷ 2 = 157
L ling kecil = phi.r.r
3,14.2.2
= 12,56
arsir = 157-12,56