Panjang jari jari OA adalah

sudut pusat lingkaran = < AOB = 120°
panjang busur AB = 44 cm
jari-jari ( r) = ?
panjang busur = <AOB/360°× keliling lingkaran
44 = 120° /360° × 2× 22/7 × r
44 = 1/3 × 44/7 × r
44 = 44/21 × r
r = 21/44 × 44
r = 21 cm
panjang jari-jari OA = 21cm