Pada segitiga ABC, b = 1, B=30°,C= 53,1°. hitunglah c!

1.gunakan aturan sinus:
c/sin C=b/sin B
20/sin 30˚ = b/sin 45˚
20/(1/2) = b/(1/2√2)
20.1/2√2=1/2b
10√2 = 1/2 b
20√2 = b (jawaban d)

2.aturan cosinus:
AC²=AB²+BC²-2.AB.BC.cos B
AC²=7²+4²-2.7.4.cos 120˚
AC²=49+16-56.(-1/2)
AC²=65+28
AC²=93
AC=√93(jawaban A)

3.soalnya lengkap gak ya?

4.PQR,PQ=20,
aturan sinus:
PQ/sin R= QR/sin P
20/sin 30˚ = QR/sin45˚
20/(1/2) = QR/(1/2√2)
40.1/2√2 = QR
20√2 = QR (jawaban A)


*jadikan yg terbaik yaa