[tex]\measuredangle ABC=\measuredangle ABD+\measuredangle DBC[/tex]
Explanation
Step 1
draw a diagram of the described situation.
Now, we can see that due to point D is in the interior, the line BC divide the angle ABC into 2 angles, angles ABD and DBC
so, we can conclude
angle ABC is the sum of angles ABD and DBC
[tex]\measuredangle ABC=\measuredangle ABD+\measuredangle DBC[/tex]
I hope this helps you
