Hence, \( \angle DEC =27^{\circ} \).
Example 15. In the adjoining figure, \( AD \) is a diameter of a circle with centre \( O \). If \( AD \) is parallel to \( BC \) and \( \angle CBD =32^{\circ} \), find
(i) \( \angle OBD \)
(ii) \( \angle AOB \)
(iii) \( \angle BED \)
(2016)
Solution. (i) Given \( AD \| BC , \angle ODB =\angle CBD \) (alt. \( \angle s \) )
But \( \angle C B D=32^{\circ} \)
314
Understanding ICSE Mathematics - X
