i hope it can help u!!!!!!!!!!
Answer:
I suppose you're trying to make a triangle of some sort on a plane! So, in this case, yes the three points would reside all on the same plane. Making all three of them collinear.
2. Angle Addition Postulate as they are adding both angles
3. 60 + 40 = m <ABC because it's a substitution
4. 100 = m <ABC as it is simplified already
5. Definition of obtuse angle
The second choice is correct
