Jawabanmu

2014-03-05T16:27:36+07:00
120/72= x/12,8 (kali silang)
72x=120 x 12,8
x = 1536/72
x = 21,33 cm
sory kalo salah......
2014-03-05T16:29:52+07:00
120 / 72 = luas juring aob / 12,8

120 x 12,8 : 72= 21,3333333 cm²