Given:
In the circle,
and
.
To find:
The following measures:
(a)

(b)

Solution:
According to the central angle theorem, the central angle is always twice of the subtended angle intercepted on the same same arc.




In a cyclic quadrilateral, the opposite angles are supplementary angles.
UVWX is a cyclic quadrilateral. So,
[Opposite angles of a cyclic quadrilateral]
Now,
[Opposite angles of a cyclic quadrilateral]
Therefore,
and
.