Solve the right triangle

Need solving this 2nd limit problem.

The equation of line wx is y=2x-5. write an equation of a line perpendicular to line wx in slopeintercept form the contains points (-1,-2)

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.