Jawaban:

140 cm

Penjelasan dengan langkah-langkah:

Lp balok = 700 cm^2

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × l

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 350

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 350

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 350

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 350

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cm

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cmp = 2l t = 1/2 × l

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cmp = 2l t = 1/2 × l= 2×10 = 1/2 ×10

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cmp = 2l t = 1/2 × l= 2×10 = 1/2 ×10= 20 cm = 5 cm

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cmp = 2l t = 1/2 × l= 2×10 = 1/2 ×10= 20 cm = 5 cmjumlah panjang rusuk = 4×(p + l + t)

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cmp = 2l t = 1/2 × l= 2×10 = 1/2 ×10= 20 cm = 5 cmjumlah panjang rusuk = 4×(p + l + t)= 4×(20+10+5)

Lp balok = 700 cm^2p : l : t = 4 : 2 : 1p : l = 4 : 2 l : t = 2 : 1p = 4/2 × l t = 1/2 × l= 2 × lLp = 2 × (pxl + l×t + pxt) = 700p×l + l×t × p×t = 3502l×l + l×1/2l +2l×1/2l = 3502l^2 + 1/2l^2 + l^2 = 3503 1/2 l^2 = 3507/2 l^2 = 350l^2 = 2/7 × 350 =100= 100l^2 = 10^2l = 10 cmp = 2l t = 1/2 × l= 2×10 = 1/2 ×10= 20 cm = 5 cmjumlah panjang rusuk = 4×(p + l + t)= 4×(20+10+5)= 4×35

= 140 cm

= 140 cmjawab 140 cm