Three reflections is a reflection or a glide reflection
The blue triangle is reflected across the red line to produce the red triangle. Then the red triangle is reflected across the purple line to produce the purple triangle. Finally, the purple triangle is reflected across the orange line to make the orange triangle.
When the three lines are parallel and when they all intersect at one point, the orange triangle is a reflection of the blue triangle. Otherwise, the orange triangle is obtained from the blue triangle by a glide reflection.