Kak tolong pakai cara

D1
AB = c = 5 cm
A = 90°
C = 30°
D2
BC = a = ?
D3
[tex] \frac{a}{ \sin(a) } = \frac{c}{ \sin(c) } \\ \frac{a}{ \sin(90 ) } = \frac{5}{ \sin(30) } \\ \frac{a}{1} = \frac{5}{ \frac{1}{2} } \\ \frac{1}{2} a = 5 \\ a \: = 5 \times 2 \\ a = 10[/tex]

sindemi :---> sinus depan miring

sin 30° = 5 / BC
       1/2 =5 /BC
          BC= 5 x 2
              = 10 cm

jawab.B