Chapter 12.7, Problem 18E

To determine

To find the coordinates of the original triangle.

Answer to Problem 18E

The coordinates of the vertices of the original triangle are $\text{P'}\left(4,2\right)\text{,Q'}\left(4,-2\right)\text{ and R'}\left(0,-2\right)$

The image of the original triangle is given below:

  

Explanation of Solution

Given information:

The following triangle is dilated using a scale factor $2$ and reflected in the y-axis.

  

The coordinates of the image are $\text{P"}\left(-4,2\right)\text{,Q"}\left(-4,-2\right)\text{ and R"}\left(0,-2\right)$

Calculation :

The coordinates of the triangle before reflection in the y-axis is:

  $\text{P'}\left(4,2\right)\text{,Q'}\left(4,-2\right)\text{ and R'}\left(0,-2\right)$

The coordinates of the triangle before dilation is:

  $\text{P}\left(2,1\right)\text{,Q}\left(2,-1\right)\text{ and R}\left(0,-1\right)$

The coordinates of the vertices of the original triangle are $\text{P'}\left(4,2\right)\text{,Q'}\left(4,-2\right)\text{ and R'}\left(0,-2\right)$

The image of the original triangle is given below: