Determine the missing information in the paragraph proof. given: line pq contains points (w, v) and (x, z) and line p'q' contains points (w + a, v + b) and (x + a, z + b). lines pq and p'q' are parallel. prove: parallel lines have the same slope. since slope is calculated using the formula , the slope of both lines is equivalent to it is given that the lines are parallel, and we calculated that the slopes are the same. therefore, parallel lines have the same slopes.