Tolong bantu guys, No 28-36. Please tolong pake caranya!

28.) A . 726 cm ......................

28) L.alas = 81 cm^2
sisi = akar dari 81
s = 9 cm
V= 9^3 cm
V = 729 cm^3
29) V balok = plt
V = 21×8×12 dm
= 2.016 dm^4
30) rusuk prisma = 3n = 3 (5) = 15 cm
sisi prisma = n + 2 = (5)+ 2=7 cm
31) Lp = 2×L.a+ Lselimut
= 2×24+240
= 288 cm^2
34) rusuk limas = 2n = 2 (6) = 12 cm