Let's remember one of the most important rules of a triangle!
- All angles must add up to 180 degrees!
With that in mind, let's add the angles that we know together.
We know two angles, simply meaning the last angle should be able to make 180 degrees when added to 160.5.
Let's make it easier- we can subtract 160.5 from 180!
Thus, the missing angle is 19.5 degrees!
Please let me know if this helped, or if you have any questions!