Draw a line segment XY = 10.3 cm
Take X and Y as centres, draw two arcs of the same radius intersecting at C and D.
Join the points C and D.
Mark the point of intersection of XY and CD as M. Perpendicular bisector passes through the midpoint. Thus, M is the mid point of XY.
∴ XM = MY (∵ M is the mid point of XY)
XY = XM + MY
= XM + XM
= 2XM
= 2MY
Hence, XY = 2XM = 2MY