CPM Homework Help : CCG Problem 6-10

Multiple Choice: $ΔABC$ is defined by points $A(3,2)$ , $B(4,9)$ , and $C(6,7)$ . Which triangle below is the image of $ΔABC$ when it is rotated $90^\circ$ counter-clockwise ( $\circlearrowleft$ ) about the origin?

$A'(-2,3)$ , $B'(-9,4)$ , $C'(-7,6)$

$A'(-3,2)$ , $B'(-4,9)$ , $C'(-6,7)$

$A'(-2,3)$ , $B'(-7,6)$ , $C'(-9,4)$

$A'(2,-3)$ , $B'(9,-4)$ , $C'(7,-6)$

none of these

Hint:

The original coordinates of point $A$ were $(3,2)$ . How are the coordinates of point $A'$ related to point $A$ ?

Use the table in the eTool below to enter the points from each choice above. When adding points to the table below, copy the first point again at the end to connect.
Click the link at the right for the full version: 6-10 HW eTool