Jawaban:

Lp balok = 700 cm^2

p : l : t = 4 : 2 : 1

p : l = 4 : 2 l : t = 2 : 1

p = 4/2 × l t = 1/2 × l

= 2 × l

Lp = 2 × (pxl + l×t + pxt) = 700

p×l + l×t × p×t = 350

2l×l + l×1/2l +2l×1/2l = 350

2l^2 + 1/2l^2 + l^2 = 350

3 1/2 l^2 = 350

7/2 l^2 = 350

l^2 = 2/7 × 350 =100

= 100

l^2 = 10^2

l = 10 cm

p = 2l t = 1/2 × l

= 2×10 = 1/2 ×10

= 20 cm = 5 cm

jumlah panjang rusuk = 4×(p + l + t)

= 4×(20+10+5)

= 4×35

= 140 cm

jawab C. 140 cm

Penjelasan dengan langkah-langkah:

semoga bermanfaat