For "O" level E. Maths students to take note,
A recent trend is to identify the centre of a circle.
The centre of a circle can be
(a) the intersection point of 2 perpendicular bisectors
(b) the mid point of the hypothenuse of a right-angled triangle
(angle in a semi circle)
(c) the vertex of larger angle which is twice the vertex of the smaller angle of
2 triangles sharing the same base.
(angle at the centre is twice the angle at the circumference)