A composition of reflections across two parallel lines is a translation. | A composition of reflections across two intersecting lines is a rotation. |
What is the image of R reflected first across line
As you do the two reflections, keep track of the distance moved by a point P of the preimage.
How do you know that
All three statements are true by the definition of reflection across a line.
The red arrow shows the direction of the translation, so the direction of the translation is determined by a line perpendicular to