The medial triangle mT of triangle T is the triangle formed by joining the midpoints of the sides of triangle T.

If the optional argument is given and is a list of three names, these three names will be assigned to the three vertices of the medial triangle mT

For a detailed description of the medial triangle mT, use the routine detail (i.e., detail(mT))

Note that the routine only works if the vertices of triangle T are known.

The command with(geometry,medial) allows the use of the abbreviated form of this command.