Draw a line l. Draw a line parallel to line l at a distance of 3.5 cm.

Steps of construction:

(1) Make a line ‘l’ and take point O on it.

(2) With O as a centre and a certain radius, draw an arc intersecting the line ‘l’ at two points P and Q.

(3) With P and Q as centres and a radius greater than OP, draw two arcs, which cut each other at R.

(4) Join OR and produce it to a certain point. Then OR is perpendicular to ‘l’.

(5) With O as centre and radius of 3.5 cm, draw an arc intersecting the ray OR at point M.

(6) With M as a centre and a certain radius, draw an arc-intersecting ray OM at two points T and S.

(7) With S and T as centres and radius greater than MS, draw two arcs, which cut each other at N.

(8) Join MN; then MN is parallel to line ‘l’.

Thus, line ‘m’ is parallel to line ‘l’.