Question

Find the coordinates of image $\overline{PQ}$ under reflection about the $y$-axis, where $P(3,2)$ and $Q(1,0)$.

• A. $P^{\prime }(3,2),Q^{\prime }(-1,0)$
• B. $P^{\prime }(-3,2),Q^{\prime }(-1,0)$
• C. $P^{\prime }(-3,-2),Q^{\prime }(-1,0)$
• D. $P^{\prime }(3,-2),Q^{\prime }(1,0)$

Answer 1

The correct option is B $P^{\prime }(-3,2),Q^{\prime }(-1,0)$

Reflection about the y-axis: $(x,y)\to (-x,y)$
$P(3,2)$ is $3$ units to the right of the $y$-axis. Therefore, the coordinates of $P^{\prime }$ are $(-3,2)$.
$Q(1,0)$ is $1$ unit to the right of the $y$-axis. Therefore, the coordinates of $Q^{\prime }$ are $(-1,0)$.


$\overline{P^{\prime }{Q}^{\prime }}$ is the image of $\overline{PQ}$ under reflection about the $y-$axis.