5. Find the unknown angle 'z'

 

In the figure, \(O\) is the centre of the circle and \(ABCD\) is a cyclic quadrilateral. If \(x\) \(=\) 21\(^{\circ}\) and \(y\) \(=\) 43\(^{\circ}\), find the unknown angle \(z\).

 

Answer:

 

The value of \(z\) is \(^{\circ}\).