hitung la panjang PR

PR^2 = PQ^2 + QR^2 - 2 . PQ . QR cos 120°
PR^2 = 6^2 + 8^2 - 2 . 6 . 8 . (-1/2)
PR^2 = 36 + 64 + 48
PR = √148
PR = 2√37 cm

QR/(sin P) = PR/(sin Q)
8/(sin P) = 2√37 / (1/2 √3)
2√37 sin P = 8 . 1/2 √3
2√37 sin P = 4√3
sin P = (4√3)/(2√37) = 2√3/√37 . √37/√37 = 2√111 /37
P = 34,71°

R = 180° - (120° + 34,71°) = 25,29°