Page 10 - Matematik Tam_Modul A+_Pan Asia Publications

Uji Kendiri 1.2

1. Rajah menunjukkan sebuah sektor AOB berpusat O dan 2. Rajah menunjukkan sebuah semi bulatan berpusat O
berjejari 8 cm. dan sebuah sektor APB dengan pusat P yang berjejari
The diagram shows a sector AOB with centre O and a radius 10 cm.
of 8 cm. The diagram shows a semicircle with centre O and a sector APB
with centre P and a radius 10 cm.
A
SP 1.3.1 8 cm 12 cm

O θ A O B
B
10 cm
1.4 rad
Diberi panjang lengkok AB ialah 12 cm, cari
Given the length of arc AB is 12 cm, find P
(a) sudut q, Cari/Find
the angle q, (a) jejari semi bulatan itu,
(b) panjang perentas AB. the radius of the semicircle,
the length of the chord AB. KBAT Mengaplikasi (b) perimeter rantau berlorek itu.
the perimeter of the shaded region.
(a) 8q = 12 KBAT Mengaplikasi
q = 12 1.4
8 (a) 1.4 rad = × 360°
2π
= 1.5 rad = 80.21°
(b) 1.5 rad = 1.5 × 360°
2π [ 80.21° ] OB
= 85.94° sin 2 = 10
Panjang perentas AB OB = 6.44 cm
2
2
2
= ! 8 + 8 – 2(8) kos 85.94° (b) Perimeter = 6.44π + 10(1.4)
= ! 118.937 = 34.23 cm
= 10.91 cm
(b) ©PAN ASIA PUBLICATIONS

1.3 Luas Sektor Suatu Bulatan Buku Teks
Area of Sector of a Circle m.s. 12-19

1. Hitung luas rantau berlorek yang berikut berdasarkan syarat-syarat yang diberi.
Calculate the area of shaded region of the following based on the given conditions. TP 3

Contoh/Example (a) Luas
Gunakan / Use 1
2
1.4 = Luas / Area 3.5 cm = 2 (3.5) (2.2)
2π πj 2 O 2
j = 10 cm 2.2 rad = 13.48 cm
O B Luas / Area
1.4 rad 1.4
= (10) 2
2
= 70 cm 2
A

(c) 4.5 cm O
7.2 cm θ q = π
3θ 4
0.4 rad 3q = 3π
4
Luas Luas
( )
= 1 (7.2) (0.4) = 1 (4.5) 2 3π
2
2 2 4
= 10.37 cm 2
= 23.86 cm 2

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