Question

Trapezoid WKLX has vertices W(2, −3), K(4, −3), L(5, −2), and X(1, −2). Trapezoid WKLX was reflected across the y-axis to produce trapezoid WꞌKꞌLꞌXꞌ.

Which coordinates describe the vertices of the image?


A.
Wꞌ(2, 3), Kꞌ(4, 3), Lꞌ(5, 2), and Xꞌ(1, 2)

B.
Wꞌ(−2, −3), Kꞌ(−4, −3), Lꞌ(−5, −2), and Xꞌ(−1, −2)

C.
Wꞌ(−3, −2), Kꞌ(−3, −4), Lꞌ(−2, −5), and Xꞌ(−2, −1)

D.
Wꞌ(–3, 2), Kꞌ(4, –3), Lꞌ(–2, 5), and Xꞌ(–2, 1)

Answer 1

Let's look at a reflection across the y-axis.
We start with point P with coordinates (a, b).

Answer 2

Okay

Answer 3

Notice that point P(a, b) becomes point P'(-a, b) after it is reflected across the y-axis.
What change do you notice between (a, b) and (-a, b) ?