In the following fiure. O is the centr of the circle and AD is the diameter. If `angle ACB =135^@` , then find `angle DOB`.

In the following figure, O is the centre of the circle , AC is the diameter and if angle APB =120^@ , then find angle BQC .

In the following figure, O is the centre of the circle. AB and CD are equal chords. If angle AOB=100^@ , Find the angle CED .

In the following figure, AB is an arc of the circle, C and D are the points on the circle. If angle ACB=30^@ , Find angle ADB .

In the adjoining figure, O is the centre of the circle. Find the value of angle BEC .

In the adjoining figure, O is the centre of the circle. Find the value of angle BEC .

In the adjoining , O is the centre of the circle. ACB is a segment. If angle OAB=30^(@) , then find the value of angle ACB .

In the adjoining , O is the centre of the circle. ACB is a segment. If angle OAB=30^(@) , then find the value of angle ACB .

In the adjoining firgure O is the centre of the centre and AB is the diameter. If angle BCE=20^(@), angle CAE= 25^(@) , then find the value of angle AEC .

In the following figure, O is the centre of the circle. AB is an arc of the circle, such that angle AOB=80^@ .Find angle ACB .