Penyelesaian Segitiga - Petua Sinus

Rajah menunjukkan sebuah segitiga ABC. Dengan menggunakan petua sinus, hitungkan nilai x.

• 12.034 cm

• 11.05 cm

• 16.98 cm

• 10.32 cm

Answer explanation

a = x, A = 25, b = 15, B = 35

$\frac{x}{\sin25}=\frac{15}{\sin\ 35}$

$x=\frac{15}{\sin\ 35}\times\sin\ 25$

$x=11.05\ cm$

Rajah menunjukkan segitiga ABC. Cari nilai x.

• 12.53 cm

• 13.53 cm

• 18.53 cm

• 11.43 cm

Answer explanation

a = x, A = 125, b = 8, B = 35

$\frac{x}{\sin125}=\frac{8}{\sin35}$

$x=\frac{8}{\sin35}\times\sin125$

$x=11.43\ cm$

Rajah menunjukkan sebuah segitiga PQR dengan panjang QR ialah 700 m, $\angle PQR\ =\ 40^{\degree}$  dan  $\angle PRQ=30^{\degree}$ . Cari panjang PQ.

• 412.54 m

• 366.14 m

• 372.46 m

• 445.90 m

Answer explanation

a = PQ, A = 30, b = 700, B = 110

 $\frac{PQ}{\sin30}=\frac{700}{\sin110}$  

 $PQ=\frac{700}{\sin110}\times\sin30$ 

 $PQ=372.46\ m$  

Cari nilai $\theta$  dengan menggunakan petua sinus.

•  $36.59\degree$  

•  $45.98\degree$  

•  $57.44\degree$  

•  $23.69\degree$  

Answer explanation

A =  $\theta$  , a = 9.2, B = 100, b = 15.2

 $\frac{\sin\ \theta}{9.2}=\frac{\sin100}{15.2}$  
 $\sin\theta=\frac{\sin100}{15.2}\times9.2$  
 $\theta=\sin^{-1}\left(0.5961\right)$  
 $\theta=36.59\degree$  

Cari nilai c.

• $25.16\degree$

• $28.88\degree$

• $30.25\degree$

• $29.77\degree$

Answer explanation

A = c, a = 7.82, B = 110, b = 14.8

$\frac{\sin\ c}{7.82}=\frac{\sin110}{14.8}$
$\sin c=\frac{\sin110}{14.8}\times7.82$
$\sin c=0.4965$
$c=\sin^{-1}\left(0.4965\right)$
$c=29.77\degree$