Berapakah panjang PQ dan QR?

∆PQR siku di Q

R = 30°
sin R = PQ/PR
PQ = PR × sin R
PQ = 13 × sin 30°
PQ = 13 × 1/2
PQ = 6,5 cm

cos R = QR/PR
QR = PR × cos 30°
QR = 13 × 1/2 √3
QR = 13/2 √3 cm