bantu ya kak? dgn jls

20)6liter/detik=6÷1/60menit=6×60=360liter/menit
80.000cm3/menit=80.000÷1000liter=80liter/detik

=360+80
=440dm3/menit

21)L=1/2×phi×r×r
r=28/2=14cm
=1/2×22/7×14×14
=308cm2

22)V=La×t
La=20×12÷2
=120dm2
V=120×18
=2160dm3