Tolong jawab segera soalnya itu mau dikumpul besok
1). Jari-jari = 15 cm
A].
Diameter = jari-jari x 2
Diameter = 15 x 2
Diameter = 30 cm
B].
Keliling = 2 x π x r
Keliling = 2 x 3,14 x 15
Keliling = 2 x 47,1
Keliling = 94,2 cm
C].
Luas = π x r²
Luas = 3,14 x 15²
Luas = 3,14 x 225
Luas = 706,5 cm²
2). Diameter = 7 cm
A].
Jari-jari = Diameter/2
Jari-jari = 7/2
Jari-jari = 3,5 cm
B].
Keliling = 2 x π x r
Keliling = 2 x 22/7 x 3,5
Keliling = 2 x 11
Keliling = 22 cm
C].
Luas = π x r²
Luas = 22/7 x 3,5²
Luas = 22/7 x 12,25
Luas = 38,5 cm²
3). Keliling = 66 cm
A].
Keliling = 2 x π x r
66 = 2 x 22/7 x r
66 = 44/7r
r = 66 x 7/44
r = 10,5 cm
B].
Diameter = Jari-jari x 2
Diameter = 10,5 x 2
Diameter = 21 cm
C].
Luas = π x r²
Luas = 22/7 x 10,5²
Luas = 22/7 x 110,25
Luas = 346,5 cm²
4). Luas = 314 cm²
A].
Luas = π x r²
314 = 3,14 x r²
r² = 314/3,14
r² = 100
r = √100
r = 10 cm
B].
Diameter = jari-jari x 2
Diameter = 10 x 2
Diameter = 20 cm
C].
Keliling = 2 x π x r
Keliling = 2 x 3,14 x 10
Keliling = 62,8 cm
1. diameter = 2 × 15 = 30
2.
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