Question

what is the rule for the reflection? (r_{y = x}(x,y)\to(y,x)) (r_{y=-x}(x,y)\to(-y,-x)) (r_{y = -x}(x,y)\to(y,x)) (r_{y = x}(x,y)\to(-y,-x))

Explanation:

Step1: Observe point - mapping

For example, if a point $(x,y)$ on $\triangle ABC$ and its corresponding point on $\triangle A'B'C'$. We can see that $(x,y)$ changes to $(-y,-x)$.

Answer:

$r_{y = -x}(x,y)\to(-y,-x)$