Penjelasan

Balok merupakan bangun ruang 3 dimensi yang dibentuk oleh 3 pasang persegi atau persegi panjang dengan paling tidak satu pasang diantaranya berukuran berbeda. Balok memiliki 6 sisi, 12 rusuk, dan 8 titik sudut. Balok memiliki elemen-elemen yaitu panjang, lebar, dan tinggi.

Rumus Luas permukaan balok :

• 2 x (( p x l ) + ( p x t ) + ( l x t ))

Rumus Volume balok :

• p x l x t

Keterangan :

• p = panjang
• l = lebar
• t = tinggi

Penyelesaian

no.1

Lp = 2 x (( p x l ) + ( p x t ) + ( l x t ))

    = 2 x (( 10 cm x 5 cm ) + ( 10 cm x 8 cm ) + ( 5 cm x 8 cm ))

    = 2 x ( 50 cm² + 80 cm² + 40 cm² )

    = 2 x 170 cm²

    = 340 cm²

V = p x l x t

  = 10 cm x 5 cm x 8 cm

  = 50 cm² x 8 cm

  = 400 cm³

_______________________________________

no.2

Lp = 2 x (( p x l ) + ( p x t ) + ( l x t ))

    = 2 x (( 15 cm x 10 cm ) + ( 15 cm x 12 cm ) + ( 10 cm x 12 cm ))

    = 2 x ( 150 cm² + 180 cm² + 120 cm² )

    = 2 x 450 cm²

    = 900 cm²

V = p x l x t

  = 15 cm x 10 cm x 12 cm

  = 150 cm² x 12 cm

  = 1.800 cm³

______________________________________

no.3

Lp = 2 x (( p x l ) + ( p x t ) + ( l x t ))

    = 2 x (( 25 cm x 20 cm ) + ( 25 cm x 15 cm ) + ( 20 cm x 15 cm ))

    = 2 x ( 500 cm² + 375 cm² + 300 cm² )

    = 2 x 1.175 cm²

    = 2.350 cm²

V = p x l x t

  = 25 cm x 20 cm x 15 cm

  = 500 cm² x 15 cm

  = 7.500 cm³

______________________________________

no.4

Lp = 2 x (( p x l ) + ( p x t ) + ( l x t ))

    = 2 x (( 20 cm x 10 cm ) + ( 20 cm x 12 cm ) + ( 10 cm x 12 cm ))

    = 2 x ( 200 cm² + 240 cm² + 120 cm² )

    = 2 x 560 cm²

    = 1.120 cm²

V = p x l x t

  = 20 cm x 10 cm x 12 cm

  = 200 cm² x 12 cm

  = 2.400 cm³

_____________________________________

no.5

Lp = 2 x (( p x l ) + ( p x t ) + ( l x t ))

    = 2 x (( 30 cm x 15 cm ) + ( 30 cm x 17 cm ) + ( 15 cm x 17 cm ))

    = 2 x ( 450 cm² + 510 cm² + 255 cm² )

    = 2 x 1.215 cm²

    = 2.430 cm²

V = p x l x t

  = 30 cm x 15 cm x 17 cm

  = 450 cm² x 17 cm

  = 7.650 cm³

Terima kasih