Question

Triangle XYZ has vertices X(1, 3), Y(0, 0), and Z(–1, 2). The image of triangle XYZ after a rotation has vertices X'(–3, 1), Y'(0, 0), and Z'(–2, –1). Which rule describes the transformation?

Answer 1

Rotate by angle α = 90°, around a center point (0; 0)
$R^{\alpha=90^o}_{(0;0)}(\Delta XYZ)=\Deltza X'Y'Z'$