bantu jawab pakai caranya juga ya biar ngerti saya

a/12 = 10/15
15a = 12 x 10
a = 120/15
a = 8 (C)

a = ?
a/12 = 10/15
a/12 = 10/15
a.15 = 12.10
a = 120/15
a = 8

semoga bermanfaat....