In the figure, O is the circumcentre of the triangle ABC, AB = AC and the line OD is perpendicular to the side BC. If BC = 8 cm and OD = 3 cm, then find the circumradius.
5 cm
Given AB = AC, OD ⊥ BC, BC = 8 cm and OD = 3 cm
We know that that perpendicular from the centre bisects the chord. Also given BC = 8 cm.
So, BD = 4 cm
Join OB.
Now, (OB)2=(BD)2+(OD)2=42+32=16+9=25
∴OB=circumradius=5 cm