Consider the following in $2D:$ Two lines $AB$ and $CD$ intersect at a point $K$, such that the angle between them is $t$ degrees. A triangle $\Delta PQR$ is first reflected about line $AB$, then about line $CD$. After the reflections, the triangle transforms to $\Delta P'Q'R'$. Now, $\Delta P'Q'R'$ is also related to $\Delta PQR$ via a single $2\times 2$ rotation transformation $T_R$. $T_R$ rotates the triangle by an angle _____ degrees, about the point _____.
