bantuin nomor 21.?????

jari2 = 6cm : 2 = 3cm

volume tabung + volume bola = r2 x 3,14 x t + 4/3 x 3,14 x r3
= 3cm x 3cm x 3,14 x (26cm-6cm) + 4/3 x 3,14 x 3cm x 3cm x 3 cm
=565,2cm3 + 113,04cm3
=678,24cm3

perbandingan logam = berat jenis
berat logam : 678,24cm3 = 10g : 1cm3
berat logam = 10g : 1cm3 x 678,24cm3
                   = 6782,4g
                   = 6,7824kg
                   = 6,78kg