In the diagram below you can see there is an object in front of a mirror, and a person at the bottom looking into the mirror. The challenge here is to find the position of the virtual image the person is seeing behind the mirror.

The law of reflection must be followed where the rays reflects off the mirror.

This next set of photos shows where the real mirror would go in the diagram, and what the person would see. It also shows how to draw the two construction lines:

Where the two virtual light rays meet, this is the position of the virtual image. The virtual image should be symmetrically opposite to the object with respect to the image. The location of the image should be exactly the same distance behind the mirror as the distance between the object and the mirror: