liwonsubagyo
15 x 4 = 60 , 12 x 4 = 48, 60 + 48 = 108 , 144 - 108 = 36 , 36: 4 = 9 jadi tingginya 9 cm Volume p x l x t = 15 x 12 x 9 = 1620 cm³ Luas permukaan balok = 2 ( p x l + p x t + l x t ) = 2 ( 15 x 12 + 15 x 9 + 12 x 9 ) = 2 ( 180 + 135 + 108 ) = 2 x 423 = 846