What must be true if triangles RST and XYZ are similiar?

If two triangles ∆RST and ∆XYZ are similar, then corresponding angles are equal and their corresponding sides are proportional.
So here $\angle R = \angle X$, $\angle S = \angle T$ and $\angle T = \angle Z$ and
$\frac{R S}{X Y} = \frac{S T}{Y Z} = \frac{R T}{X Z}$