Perbandingan panjang lebar dan tinggi sebuah balok adalah p : l : t = 5 : 2 : 1 , jika luas permukaan balok 306cm², maka tentukan besar volume balok tersebut

Lp = 2(p × l) + 2(l × t) + 2(p × t).
306 = 2(5x × 2x) + 2(2x × x) + (5x × x).
306 = 2(10x⁲)+ 2(2x⁲) + 2(5x⁲).
306 = 20x⁲ + 4x⁲ + 10x⁲.
306 = 34x⁲.

x⁲ = 306/34.
x⁲ = 9.
x = √9.
x = 3.

V. Balok
= p × l × t.
= 5x × 2x × x.
= 5(3) × 2(3) × 3.
= 15 × 6 × 3.
= 270cm⁳.

L = 2(pxl+ lxt + pxt)
306 = 2(5a × 2a + 2a × a + 5a × a)
306 = 2(10a² + 2a² + 5a²)
306 = 34a²
306 : 34 = a²
9 = a²
3 = a

p = 5a => 5(3) = 15
l = 2a => 2(3) = 6
t = a => 1(3) = 3

V = p x l x t
= 15 x 6 x 3
= 270 cm³

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