Jawabanmu

2014-05-08T10:53:15+07:00
Volume= 20x15x40=12000
3/4x12000=9000
9000+1200=10200
volume=pxlxt
10200=20x15xt
t= 10200/(20x15)
t=10200/300=34 cm
2014-05-08T11:11:08+07:00
Volume balok = p×l×t = 20×15×40 = 12000 cm3...
1200×3/4 = 9000 cm3
9000+1200 = 10200 cm3
10200 = 20×15×t
t = 10200÷[20×15]
 = 10200 ÷ 300 = 34 cm
jadi tinggi balok = 34 cm