Line segment PQ is reflected across two lines as described below.

• WhenPQ¯¯¯¯¯is reflected over line a, the image ofP (7,−6)  is P′ (5,−1).

• WhenP′Q′¯¯¯¯¯¯¯is reflected over line b, the image ofP′ (5, 1)  is P'' (1, 9).


Which of the following is not true?

Lines a and b are parallel.
PQ,  P′Q′, and P′′Q′′ are congruent.
The midpoint of P′P′′ lies on line b.
Points Q, Q′, and Q′′ form a scalene triangle.