1) 40degrees (COB is 100, ans the triangle is iscoceles)
2) 80 degrees(twice 40 which is on the circumference...angles subtended from the same arc)
3) 65 degrees because AEDB is a cyclic quadrilateral
4)65 again cuz the lines r parallel
5) 65+50(from cyclic quadrilateral u get A 65 and from triangle COA u get A as 50)
It's quite easy