Answer:
[tex]\angle BDC=80^{\circ}[/tex]
Step-by-step explanation:
We are given that
[tex]\angle ABC=69^{\circ}[/tex]
[tex]\angle ACB=31^{\circ}[/tex]
We have to find the angle BDC.
In triangle ABC
Sum of interior angles of triangle=180 degrees
[tex]\angle ABC+\angle ACB+\angle BAC=180^{\circ}[/tex]
[tex]69+31+\angle BAC=180[/tex]
[tex]100+\angle BAC=180[/tex]
[tex]\angle BAC=180-100[/tex]
[tex]\angle BAC=80^{\circ}[/tex]
[tex]\angle BAC=\angle BDC=80{\circ}[/tex]
Angles subtended on the same are ac are equal.
[tex]\angle BDC=80^{\circ}[/tex]