Question

class 10 icse
please with reasons​

Answer 1

since Dc||AB and BC is a transversal

angle DCB=angle CBA=35°[ALTERNATE ANGLES]

now join OC and OD

since angle at the centre is twice the angle at remaining circumference

angle COA= 2CBA=2×35=70°

angle DOB=2DCB=2×35°=70°

AOE is a straight line(diameter)

angle BOD+ angle COD+ angle COA=180°

70°+ angle COD+70°=180°

angle COD =180-140

angle COD=2×CED=

(180-140/2)=20°