Question

Graph the image of rectangle QRST after a rotation 90° counterclockwise around the origin.

Answer 1

Solution

Note:

When rotating a point 90 degrees counterclockwise about the origin our point A(x,y) becomes A'(-y,x). In other words, switch x and y and make y negative.

Using the above, the image will the rectangle Q'R'S'T' is

$\begin{gathered} Q=(-9,-8) \\ Q^{\prime}=(8,-9) \\ \\ R=(-4,-8) \\ R^{\prime}=(8,-4) \\ \\ S=(-4,0) \\ S^{\prime}=(0,-4) \\ \\ T=(-9,0) \\ T^{\prime}=(0,-9) \end{gathered}$

The graph is