Question

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

Explanation:

Step1: Recall the rotation rule

When a point \((x,y)\) is rotated \(90^{\circ}\) counter - clockwise around the origin, the new coordinates \((x',y')\) follow the rule \((x,y)\to(-y,x)\).

Step2: Identify the original coordinates of point \(Q\)

From the graph, the coordinates of point \(Q\) are \((- 5,-9)\). Here \(x=-5\) and \(y = - 9\).

Step3: Apply the rotation rule

Using the rule \((x,y)\to(-y,x)\), substitute \(x=-5\) and \(y=-9\). Then \(-y=-(-9) = 9\) and \(x=-5\).

Answer:

\((9,-5)\)