Answer:
For part D, x=5.217
Explanation:
So essentially, all triangles have 180 degrees, so we an set up our equation as
55 + 8x + 15x + 5 = 180. We can simplify it to 60 + 23x = 180 by combining the like terms. Then we subtract 60 from both sides, getting us 23x = 120, and then we just divide 23 from both sides, and I just rounded the number to the thousandth place.
For part B, we an apply that same logic, and add 38 + 38 + 4x +... = 180. This gives us 76 + 4x+ ... = 180, and from there we just apply basic algebra. Hope this helps and lmk if you have and questions :D