pake cara ya makasih no.9 ^_^

l Ling b = π×r×r
=3,14×10×10
=314×1/2= 157
L Ling k=π×r×r
=3,14×4×4×1/2
=25,12+ 157= 182,12
l Ling paling b=π×r×r
=22/7×14×14
=616×1/2= 308-182,12=125,88