So,
Here we have the following vertices:
[tex]\begin{gathered} F(-9,-1) \\ G(0,-1) \\ H(-9,-2) \end{gathered}[/tex]We're going to rotate these vertices 270° clockwise around the origin.
Remember that a 270° clockwise rotation around the origin follows the rule:
[tex](x,y)\to(-y,x)[/tex]So, if we apply this rule to our points, we obtain:
[tex]\begin{gathered} F(-9,-1)\to F^{\prime}(1,-9) \\ G(0,-1)\to G^{\prime}(1,0) \\ H(-9,-2)\to H^{\prime}(2,-9) \end{gathered}[/tex]