You know that an angle is made by an arc between two lines. One of the line is called the ray. A ray starts from one point, then extends to infinitely. It is not possible because a midpoint is the center between two points. You can not find the center because the line extends infinitely.
For the first part of the question you put the unknown variable multiplied by 16.62. Then add 26 which equals an unknown variable. For the second part, I multiplied 16.62 by 7 and added 26.