Geometry Construction

Question

I am trying to reflect a triangle ABC over a line of reflection, m, using a compass. I am required to write down the tranformation rule, but I have no idea what that is. My teacher was mentioning something about little r’s and m’s but I am very confused.

Answer 1

To reflect a triangle about a line, each point on the reflected figure is the same perpendicular distance from the line of reflection as the point on the original figure but in the opposite direction.

For example: in co-ordinate terms, if the line of reflection is x=0, and (x,y) is a point in the original figure then the reflected point will be (-x,y).