Penjelasan dengan langkah-langkah:

11.

= 2πr

= 2 × 22/7 × 14

= 88 cm

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12.

= ¼πd²

= 0,25 × 3,14 × 40²

= 1.256 cm²

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13.

Keliling

= πd

= 22/7 × 28

= 88 cm

Jarak tempuh

= keliling × roda berputar

= 88 × 10.000

= 880.000 cm

= 8,8 km

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14. persegi panjang

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15. a. persegi panjang

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16.

= 2(pl + pt + lt)

= 2(20 × 80 + 20 × 70 + 80 × 70)

= 2 × 8.600

= 17.200 cm²

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17.

= r³

= 15³

= 3.375 cm³

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18.

Volume balok

= plt

= 40 × 100 × 1,5

= 6.000 m³

Volume air

= volume balok × kolam terisi

= 6.000 × ⅘

= 4.800 m³

= 4.800.000 liter

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19.

Luas balok

= 2(pl + pt + lt)

= 2(10 × 8 + 10 × 1,5 + 8 × 1,5)

= 2 × 107

= 214 m²

Harga

= luas balok × biaya

= 214 × 3.000

= Rp 642.000

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20.

= 6r²

= 6 × 30²

= 5.400 cm²

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21.

= panjang rusuk × banyak rusuk

= 25 × 12

= 300 cm

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22.

Keliling kubus

= panjang rusuk × banyak rusuk

= 12 × 12

= 144 cm

sisa kawat

= panjang kawat - keliling kubus

= 2 m - 144 cm

= 200 - 144

= 56 cm

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23.

= (2 × (at)) + ((2 × (p + l)) × t)

= (2 × (20 × 8)) + ((2 × (20 + 12)) × 30)

= (2 × 160) + (64 × 30)

= 320 + 1.920

= 2.240 cm²

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24.

= ½at∆t

= ½ × 10 × 24 × 40

= 4.800 cm³

———————————————————————

25.

= ⅓plt

= ⅓ × 12 × 8 × 10

= 320 cm³

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26.

= 2πr(r + t)

= 2 × 3.14 × 15(15 + 50)

= 2 × 3.14 × 15 × 65

= 6.123 cm²

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27.

= πr²t

= 22/7 × 35² ×20

= 77.000 cm³

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28.

Panjang garis pelukis

= ²√r² + t²

= ²√10² + 24²

= ²√676

= 26 cm

Luas

= πr(r + s)

= 3,14 × 10(10 + 26)

= 3,14 × 10 × 36

= 1.130,4 cm²

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29.

= ⅓πr²t

= ⅓ × 7² × 24

= 392 cm³