< POQ : < QOR = 3 : 6, jika panjang busur PQ = 23cm, hitunglah panjang busur QR dan keliling lingkaran!

PQ /< POQ = QR / < QOR
PQ / QR = < POQ / <QOR
23 / QR = 3 / 6
QR = 6/3 × 23
QR = 2 × 23
QR = 46 cm

keliling lingkaran
= 2 (PQ + QR)
= 2 (23 + 46)
= 2 (69)
= 138 cm