Answer:
Line of reflection is used on graphs to show identical measurement as a reflection and to understand that each shape has a point and is reflected in same direction from the line. Some lines are horizontal and some vertical, but some shapes are diagonal and its important you can label each point so that you can recount each point on grid paper to see the shape is symmetrical to the line by the same amount of squares or measurement. ie) triangle or diamond shape that appears diagonally rotated is just like a mirror image and has the distance from point A (its mirror) to the line as from the line of symmetry. Such lines are usually shown in red on grid paper.
Explanation: