Jawab b dan c ya mas makasih
Ket :
Lilitan = keliling
Area = Luas
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Bagian A
[tex] \: [/tex]
Soal 1
K = 2 × [tex]\pi[/tex] × r
176 cm = 2 × ²²/7 × r
56 cm = 2 × r
r = 56 cm ÷ 2
r = 28 cm
➝ Area
A = [tex]\pi[/tex] × r²
A = ²²/7 × 28 cm²
A = ²²/7 × 784 cm
A = 2.464 cm²
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Soal 2
K = 2 × [tex]\pi[/tex] × r
78,55 cm = 2 × 3,142 × r
25 cm = 2 × r
r = 25 cm ÷ 2
r = 12,5 cm
➝ Area
A = [tex]\pi[/tex] × r²
A = 3,142 × 12,5 cm²
A = 3,142 × 156,25 cm
A = 490,9375 cm²
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Bagian B
[tex] \: [/tex]
Soal 1
A = [tex]\pi[/tex] × r²
1.386 cm² = ²²/7 × r²
r² = 1.386 cm² × ⁷/22
441 cm = r²
r = 21 cm
➝ Lilitan/keliling
K = 2 × [tex]\pi[/tex]
K = 2 × ²²/7 × 21 cm
K = 2 × 66 cm
K = 132 cm
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Soal 2
A = [tex]\pi[/tex] × r²
452.448 cm² = 3.142 × r²
144 = r²
r = 12 cm
➝ Lilitan/keliling
K = 2 × [tex]\pi[/tex] × r
K = 2 × 3.142 × 12 cm
K = 6,284 cm × 12 cm
K = 75,408 cm
[tex] Lilitan = Circumference \\ \\ B.1).C = 2 \times \pi \times r \\ 176 = 2 \times \frac{22}{7} \times r \\ 176 = \frac{44}{7} \times r \\ 176 \times \frac{7}{44} = r \\ r = 28 \\ \\ Area \\ \pi \times r \times r \\ \frac{22}{7} \times 28 \times 28 \\ 2464 \: {cm}^{2} \\ \\ 2).C = 2 \times \pi \times r \\ 78.55 = 2 \times 3.142 \times r \\ \frac{78.55}{6.284} = r \\ r = 12.5 \\ \\ Area \\ \pi \times r \times r \\ 3.14 \times 12.5 \times 12.5 \\ 490.9375 \: {cm}^{2} \\ \\ C.1).A = \pi \times r \times r \\ 1386 = \frac{22}{7} \times {r}^{2} \\ 1386 \times \frac{7}{22} = {r}^{2} \\ {r}^{2} = 441 \\ r = \sqrt{441} = 21 \\ \\ Circumference \\ 2 \times \pi \times r \\ 2 \times \frac{22}{7} \times 21 \\ 132 \: cm \\ \\ 2).A = \pi \times r \times r \\ 452.448 = 3.142 \times {r}^{2} \\ \frac{452.448}{3.142} = {r}^{2} \\ {r}^{2} = 144 \\ r = 12 \\ \\ Circumference \\ 2 \times \pi \times r \\ 2 \times 3.142 \times 12 \\ 75.408 \: cm[/tex]
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