Question

what is the angle subtended at the centre of a quadrilateral​

Answer 1

Step-by-step explanation:

The angle subtended at the centre of a circle is double the size of the angle subtended at the edge from the same two points, ... Opposite angles in a cyclic quadrilateral add up to 180°, Alternate Segment Theorem, i.e. that the angle between a tangent and its chord is equal to the angle in the 'alternate segment'.