Let O be the centre of the circle. Draw OC ⊥ AB. OC is the distance of the chord ABfrom the centre of the circle. OB = Radius of the circle = 17 cm BC=AC=
30
2
=15cm (Perpendicular from the centre to the chord bisects the chord) In ΔABC, OC=√OB2−BC2=√172−152 =√289−225=√64=8cm