Question

Volume sebuah balok tanpa tutup 8.640 . Jika perbandingan p : l : t = 5 : 3 : 9, luas permukaan balok tersebut...

Answer 1

P:L:T= 5:3:9,,,, p= 5x, l=3 x, t=9x…………………………………………………………… 5x.3x.9x= 8640, 135x³= 8640, x³=64, x=4 cm,…………………………………… lp= 2(pl+pt+lt)= 2(20.12+20.36+12.36)= 2.1392= 2784 cm²

Answer 2

Volume balok = p x l x t
p : l : t = 5 : 3 : 9  =>  volume balok : 5x x 3x x 9x = 8640
135x³ = 8640
     x³ = = 64
     x = = 4
p = 5x = 5 x 4 = 20 cm
l = 3x = 3 x 4 = 12 cm
t = 9x = 9 x 4 = 36 cm
Luas permukaan tanpa tutup = p x l + 2 (p x t) + 2 ( l x t)
                                          = 20 x 12 + (2 x 20 x 36) + (2 x 12 x 36)
                                          = 240 + 1440 + 864
                                          = 2544 cm²

moga cukup jelas ^_^