Question

angles on same segment of circle are equal

Answer 1

given that please see the attachment for answer 

Answer 2

we know that, angle subtended by an arc of a circle at centre is double the angle subtended by the arc in alternative segment . hence,
angle AOB = 2 angle ACB 
Aangle AOB = angle ADB 
so. angle ACB= ADB
REFLEX angle AOB = 2 angle ACB
and reflex angle AOB =2 angle ADB
2 angle ACB= 2 angle ADB
angle ACB = ADB