We are asked to find the measure of angle ABC and classify the angle.
As you can see from the figure, vertex A is at 30° and vertex C is at 155°
So, the angle ABC is
![\angle ABC=155\degree-30\degree=125\degree](https://img.qammunity.org/2023/formulas/mathematics/college/6k817d1gf9o5dkqiqh8waj8wojrog4lbk6.png)
So, the angle ABC is 125°
Now recall that an obtuse angle is greater than 90° and less than 180°
Since 125° is between 90° and 180°, therefore, the angle ABC is an obtuse angle.
![m\angle ABC=125\degree,\quad obtuse](https://img.qammunity.org/2023/formulas/mathematics/college/1xaz1p5ra10es1sqdl5gto7l5pqrfn1e37.png)