Answer:
Perimeter of the Triangle

I believe they are called opposites.
M<ABC = m<EBD = 36 (vertical angles)
78 - x + 36 + 3x - 10 = 180 (straight angle)
Now solve for x
78 - x + 36 + 3x - 10 = 180
2x + 68 = 180
- 68 -68 (subtract 68 on both sides)
2x = 58
x = 29