Question

Tolong bantu kerjakan 10 nomer, Bagi2 banyak (40)poin

Kurang jelas? Bisa liat buku Mtk kls 8/genap hal 113-115

Answer 1

1.a= 90
luas juring  = 78,5
90/360 x luas lingkaran = 78,5
1/4 (3,14) r² = 78,5
r^2 = 100
r = 10

2. P.busur = 22
120°/360° x keliling lingkaran = 22
1/3 x phi x d = 22
1/3 x 22/7 x d = 22
22/21 x d = 22
d = 22 : 22/21
d = 22 x 21/22
d = 21 cm

3. panjang busur: 16,5 cm
a/360°. π .d = 16,5
a/360° . 22/7 . 42 = 16,5
a= 16,5. (7. 360°) / (22.42)
a=45°

4. Luas juring= 60/360×π×r²
57,75= 1/6×22/7×r²
57,75= 0,523×r²
r²= 57,75÷0,523
r²= 110,25
r= √110,25
r= 10,5 cm

5.Panjang busur
= α/360° . 2 . π . r
= 30°/360° . 2 . 22/7 . 21
= 1/12 . 44 . 3
= 11 cm

6. Sudut BAD
= 1/2 . sudut BOD
= 1/2 . 110°
= 55°

Sudut BCD 
= 180° - 55°
= 125°

10. Ada 2 bangun datar
1 persegi
L = s.s = 14.14 = 196

sebuah 1/2 lingkaran dg d = 14
berarti r = 14/2 = 7
L 1/2O = 1/2 . 22/7 . 7 . 7 = 77

L total = L persegi + L stengah lingkaran
= 196+77
= 273 cm^2

no 7,8 sy gatau maaf itu yg digambar no 9 ya