panjang 12 cm,lebar 10cm,tinggi 9 cm maka berapa luas permukaan balok adalah

L = 2 x [( p x l ) + ( p x t ) + ( l x t )]
L = 2 x [( 12 x 10 ) + ( 12 x 9 ) + ( 10 x 9 )]
L = 2 x [ 120 + 108 + 90 ]
L = 2 x 318
L = 636 cm²

Semoga Membantu ^_^

Lp = 2 (pxl + pxt + lxt)
= 2 ( 12 × 10 + 12 × 9 + 10 × 9 )
= 2 ( 120 + 108 + 90 )
= 2 ( 318 )
= 636 cm²