 Hi and welcome to the session. Let us discuss a foreign question. The question says in figure 10.38 This is the figure 10.38 angle ABC is equal to 69 degree angle ACB is equal to 31 degree fine angle BDC. We have to find this angle. Now before solving this question we should first be well versed with theorem 10.9 given in your NCERT book. The theorem 10.9 states that angles in the same segment of a circle are equal. Let us now understand that what does this theorem mean? We should know that called AB of a circle divides it into two segments that is major, minor segment. If we have angles in the major segment then major of all these angles are equal. So this means angle ACB is equal to angle ADB as they both are in the same segment. The knowledge of this theorem is the key idea in this question. Now beginning with this solution in the question we are given that angle ABC is equal to 69 degree and angle ACB is equal to 31 degree. In triangle ABC angle ABC plus angle ACB plus angle CAB is equal to 180 degree because sum of all angles of a triangle is 180 degree. Now substitute the value of angle ABC and angle ACB. Angle ABC is equal to 69 degree and angle ACB is equal to 31 degree. Now this implies angle CAB is equal to 180 degree minus 100 degree. So angle CAB is equal to 80 degree. Now angle CAB and angle VDC are equal because they both are in the major segment VADC and we have learnt about that angles in the same segment are equal. So angle CAB is equal to angle VDC because angles in the same segment are equal. Angle VDC is also equal to 80 degree. Hence the required answer is 80 degree. This completes the session. Bye and take care.