Lines AB and CD intersect at point O, forming four angles. One of the angles measures 112∘.
a. (i) State the theorem that relates the measures of a pair of vertically opposite angles obtained when two straight lines intersect.
b. (ii) Using the theorem stated in part (i), find the measure of the angle that is vertically opposite to the 112∘ angle.
c. (iii) Classify both the 112∘ angle and its vertically opposite angle as acute, right, obtuse, straight, or reflex. Give suitable justification for each classification.