Page 28 - Hybrid PBD 2022 Tg 5 - Matematik Tambahan

Matematik Tambahan Tingkatan 5 Bab 1 Sukatan Membulat
8. Tentukan luas sektor berlorek bagi setiap bulatan yang berikut. Beri jawapan betul kepada dua tempat
perpuluhan.
Determine the area of the shaded sector for each of the following circles. Give your answer correct to two decimal places. SP 1.3.1 TP3

(a)
4.8 cm
A O B O θ
__
6π
5
C

Diberi AOB ialah diameter dengan panjangnya q = 2π – 6π 2 rad
ialah 7.4 cm, dan /AOC = 2/BOC. 4π 5
Given AOB is the diameter of length 7.4 cm and = rad
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/AOC = 2/BOC. 5
1 2
/AOC = 2π rad L = j q
3 2
1
 2
1 2
L = j q = (4.8) 2 4π
2 2 5
1
 2
= (3.7) 2 2π = 14.34 cm 2 = 28.95 cm 2
2 3
(b) (c)
20 cm
3.8 cm
O θ 7.5 cm
θ 3.85 rad
O
q = 7.5 q = (2π – 3.85)
3.8 = 2.43 rad
= 1.97 rad Jejari / Radius = 20 = 8.23 cm
2.43
L = j q 1 2
1 2
2 L = j q
2
1
= (3.8) (1.97) 1
2
2
2 = (8.23) (2.43)
2
= 14.22 cm 2
= 82.30 cm
2
9. Tentukan jejari bagi sektor bulatan berlorek yang berikut. Beri jawapan betul kepada dua tempat perpuluhan.
Determine the radius of the following shaded sectors of circles. Give your answer correct to two decimal places. SP 1.3.1 TP4
(a) Diberi luas sektor ialah 49 cm 2
Diberi luas sektor yang berlorek ialah 2
.8 cm 2 Given the area of the sector is 49 cm .
Given the area of the shaded sector is 23.8 cm . 2
A 1.63 rad
1.78 rad
O
B
49 = 1.63
Tip Penting πj 2 2π
luas sektor q 49 × 2
2
23.8 = 1.78 Guna luas bulatan = 2π j = 1.63
πj 2 2π Use area of sector = q j = 7.75 cm
2 area of circle 2p
2
j = 23.8 ×
1.78
j = 5.17 cm

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