Question

practice performing a reflection in the coordinate plane
study the example showing a reflection across the y - axis. then solve problems 1 - 5.
example
tessa uses reflections to design a pattern. she draws figure ghij in the coordinate plane. how might she have reflected figure ghij across the y - axis to form figure ghij?
tessa could have counted the number of units from each vertex to the y - axis. then she could have counted the same number of units on the other side of the y - axis to plot the corresponding vertices of figure ghij.
1 tessa can now use her graph in the example to find the coordinates of the vertices of figure ghij. how could she have found these coordinates without drawing the reflection of figure ghij?

Explanation:

Step1: Recall reflection rule

For a reflection across the y - axis, the rule is $(x,y)\to(-x,y)$.

Step2: Apply rule to vertices

If the coordinates of the vertices of figure $GHIJ$ are $(x_1,y_1),(x_2,y_2),(x_3,y_3),(x_4,y_4)$ respectively, then the coordinates of the vertices of figure $G'H'I'J'$ are $(-x_1,y_1),(-x_2,y_2),(-x_3,y_3),(-x_4,y_4)$ respectively.

Answer:

Use the rule $(x,y)\to(-x,y)$ for each vertex of figure $GHIJ$ to find the coordinates of the vertices of figure $G'H'I'J'$.