nomor 2-5 tolong jawab

2. L = phi × r kuadrat
1386 =22/7 × r kuadrat
r kuadrat = 1386 : 22/7
= 1386 × 7/22
=63 × 7
=441
r = akar pangkat dari 441
=21
jadi,diameternya adalah
d = 2 × jari jari
=2 ×21
=42



3. K = 2 phi r
31,4 = 2 . 3,14 . r
31,4 = 6,28 . r
r = 31,4 : 6,28
= 5

jadi, L = 1/2 phi r2
=1/2 .3,14 . 5 .5
=1/2 . 3,14 .25
=1/2 . 78,5
= 39,25


4. L = 1/2 . phi . r2
= 1/2 . 22/7 . 7 .7
=1/2 . 154
=77
biaya = 77 × 500.000
=38.500.000



5. K = 2.phi.r
50,24 = 2.3,14.r
50,24 = 6,28 . r
r =50,24 : 6,28
=8

L = phi . r2
= 3,14 . 8 . 8
= 3,14 . 64
=25,12


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