Question

1. perbandingan p:l:t =5:3:2
jika volume balok 810 cm3
berapakah luas permukaan balok

Answer 1

P : L : T = 5a : 3a : 2a
 
Volume balok = P x L x T
810 = 5a . 3a. 2a
810 = 30

a = 3

P = 5a = 15
L = 3a = 9
T = 2a = 6

Luas permukaan = 2 (PL) + 2(LT) + 2(PT)
                          = (2 x 15 x 9) + ( 2 x 9 x 6) + ( 2 x 15 x 6)
                         = 558

Answer 2

Kita cari p, l, sama t.
dimisalkan a
p = 5a ; l = 3a ; t = 2a
volume = p×l×t
810     = 5a×3a×2a
810     = 30 a³
27      = a³
3        = a

p =15 cm ; l = 9 cm ; t = 6 cm
L = 2((p×l)+(l×t)+(p×t))
   = 2 ((15×9)+(9×6)+(15×6))
   = 2×279 = 558 cm²