Question

do it fast as soon as possible​ . please solve in copy then answer this

Answer 1

Step-by-step explanation:

construction- join OB

in ∆AOB, OA=OB (radius of the circle)

angleBAO = angleABO = 20°(Base angle of isosceles triangle)

similarly, in ∆ BOC

angleBCO=angleCBO=15°

now, angle ABC=angle ABO + angle CBO

=20°+15°=35°

angle AOC= 2 times angle ABC ( Angle subtended at the center is double the angle subtended by the same chord AC in this case)

now angle AOC= 2* 35=70°

again, angle ABC + angle ADC= 180° ( THE SUM OF OPPOSITE ANGLES OF A CYCLIC QUADRILATERAL IS 180°)

=35°+ angle ADC= 180°

ADC= 180°-35°

ADC= 145°

HOPE THIS HELP YOU.