Please help me with #7 i would really appreciate it and explain if you can due today

Angle 1 is 129

Step-by-step explanation:

Angle 1 and the given angle are both supplementary, meaning, both of them combined equal 180 degrees. So, you do this:

180-51=?

180-51=129

explanation:

previous steps have made pa≅ pb ≅ st ≅ su. setting the compass width to ab allows you to make tu the same length. then δstu ≅ δpab by the sss congruence postulate, and ∠p ≅ ∠s by the reason cpctc.

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.