Answer:
80
Explanation:
The total of all angles for a triangle must equal 180 degrees.
In the problem, it gives you two angles. One is 70 degrees and one is 30 degrees. If we add those angles together, we get 100 degrees. 70+30 = 100.
Now all we need is that third angle
Since the total must be 180. We can subtract 100 from it to get that final angle.
180-100 = 80