Triangle PQR is transformed to triangle P′Q′R′. Triangle PQR has vertices P(4, 0), Q(0, −4), and R(−8, −4). Triangle P′Q′R′ has vertices P′(1, 0), Q′(0, −1), and R′(−2, −1).

Question

Plot triangles PQR and P′Q′R′ on your own coordinate grid.

Part A: What is the scale factor of the dilation that transforms triangle PQR to triangle P′Q′R′? Explain your answer. (4 points)

Part B: Write the coordinates of triangle P′′Q′′R′′ obtained after P′Q′R′ is reflected about the y-axis. (4 points)

Part C: Are the two triangles PQR and P′'Q′'R′' congruent? Explain your answer.

Answer 1

A: all the coordinates are divided by 4, so ...
B: (x,y) → (-x,y)
C: clearly not, since PQR is not congruent to P'Q'R' but P'Q'R' is congruent to P"Q"R", and congruency is transitive.