CPM Homework Help : GC Problem 12-81

Multiple Choice: Assume that $A\left(6,2\right)$ , $B\left(3,4\right)$ , and $C\left(4,-1\right)$ . If $\Delta ABC$ is rotated $90º$ counterclockwise ( $\circlearrowleft$ ) to form $\Delta A'B'C'$ , and if $\Delta A'B'C'$ is reflected across the $x$ -axis to form $\Delta A''B''C''$ , then the coordinates of $C''$ are:

$\left(1,4\right)$

$\left(-4,1\right)$

$\left(1,-4\right)$

$\left(4,1\right)$

Step 1:

Graph $\Delta ABC$ .

Step 2:

Rotate the triangle $90^\circ$ counterclockwise.

Step 3:

Reflect the triangle across the $x$ -axis and then find the coordinates of the new triangle.

Triangle A (6, comma 2), B (3, comma 4), C(4, comma negative 1)

triangle added with the following coordinates: A prime (negative 2, comma 6), B prime (negative 4, comma 3), C prime (1, comma 4).

Triangle added with the following coordinates: A double prime (negative 2, comma negative 6), B double prime (negative 4, comma negative 3), C double prime (1, comma negative 4).

Click the link at right for the full version of the eTool: 12-81 HW eTool
Use this eTool to find the coordinate of C".