The angles opposite equal sides are also equal. The sum of angles in a triangle is 180. So 2x + 27 + 2x + 27 + 3x + 28 = 180.
7x + 82 = 180
7x = 98
x = 14
Now plug x into each angle to find their measures.
11x + 2 = 13x, 9x - 4 = 5x, 5x + 13x = 18x
Answer:

Step-by-step explanation:

D, B, and A are collinear. Yes they are coplanar because they all lay on the same plane. And I don’t understand the last question