The image of a preimage when is rotated 90 degrees around the origin anticlockwise is M(h, k) is M'(-k, h).
Therefore, for the triangle with points:
[tex]S(2,-1)\rightarrow S\langle-(-1),2\rangle\rightarrow S\langle1,2\rangle[/tex][tex]T(5,1)\rightarrow T\langle-1,5\rangle [/tex][tex]U(3,3)\rightarrow U\langle-3,3\rangle[/tex]
Thus, the rotation anticlockwise 90 degrees around the origin is:
S(2, -1) , S'(1, 2);
T(5, 1) , T'(-1, 5);
U(3, 3) , T"(-3, 3).
