two chords ab and cd intersect at right angles. if angle bad=30 , then find angle abc

angle ADC+angle BAD + 90 degree= 180 degree, in the triangle formed by points A,D and the intersection point(angle sum property0
therefore angle ADC can be calculated as 60 degree.
angle ADC= angle ABC(angles in the same segment are equal)
                 = 60 degree
hope it was helpful thnx 4 the question!