tolong ya nomor 1 dan 2 PAKAI JALAN

1. a = 22/7 x 21 x 21 = 1386 cm3
    b = 22/7 x 31,5 x 31,5 = 3118,5 cm3
    c = 22/7 x 28 x 28 = 2464 cm3
    d = 22/7 x 14 x 14 = 660 cm3

2 a = 3,14 x 6 x 6
      = 133,04 cm3
    b = 3,14 x 10 x 10 
       = 314 cm3
    c = 3,14 x 8 x 8 = 200,96 cm3
    d = 3,14 x 7 x 7 = 153,86 cm3

mungkin ada beberapa kesalahan
maaf kalau salah

1.a. L= phi x r x r
= 22/7 x 21 x 21
=1386 cm2

b. L= phi x r x r
= 22/7 x 31,5 x 31,5
=99 x 31,5
3118,5 cm2

c. L= phi x r x r
=22/7 x 28 x 28
=2464 cm2

d.L=  phi x r x r
= 22/7 x 14 x 14
= 616 cm2

2.a.L= phi x r x r
= 3,14 x 6 x 6
=113,04 cm2

b. L= phi x r x r
= 3,14 x 8 x 8
=200,96 cm2

c. L= phi x r x r
= 3,14 x 10 x 10
=314 cm2

d. L= phi x r x r
= 3,14 x 7 x 7
=153,86 cm2

semoga bermanfaat  :)