Let's first draw a line segment of length 7.3 cm .1) Draw a line l, mark point A on it.2) Since length is 7.3 cm, we measure 7.3 cm using ruler and compass.3) Now keeping compass opened the same length, we keep pointed end at point A and draw an arc on line l.So, the required line segment is AB = 7.3 cm .Now, we need to find its axis of symmetry.1) Given a line segment AB.2) Now with A as centre, and radius more than half AB, draw an arc on top and bottom of AB.3) Now with B as centre, and same radius, draw an arc on top and bottom of AB.4) Where the two arcs intersect above AB is point C and where the two arcs intersect below AB is point D.Join CD.CD is the line of symmetry of line segment AB.