I think what you do is in the number of children you write 0, 1, 2,3,4 the count how much times that number appears in the list and that’s your frequency, for eg Number of children = 1 Frequency = 2
Since the trapezoid can be inscribed in a circle, that means angle B + angle D = 180 degree. Since AB is parallel to CD, then angle B + angle C = 180 degree. Therefore, angle D = angle C.
