Question

write the coordinates of the vertices after a rotation 90° counterclockwise around the origin.

Explanation:

Step1: Recall rotation rule

The rule for a 90 - degree counter - clockwise rotation around the origin is $(x,y)\to(-y,x)$.

Step2: Identify original coordinates

From the graph, the coordinates of point $C$ are $(0,9)$, for point $D$ are $(4,9)$ and for point $E$ are $(0,3)$.

Step3: Apply rotation rule to point C

For $C(0,9)$, using the rule $(x,y)\to(-y,x)$, we get $C'(-9,0)$.

Step4: Apply rotation rule to point D

For $D(4,9)$, using the rule $(x,y)\to(-y,x)$, we get $D'(-9,4)$.

Step5: Apply rotation rule to point E

For $E(0,3)$, using the rule $(x,y)\to(-y,x)$, we get $E'(-3,0)$.

Answer:

$C'(-9,0)$
$D'(-9,4)$
$E'(-3,0)$