Solution:

Steps to construct:

Step 1: Draw a line segment BC = 4cm.

Step 2: With centers B and C, draw two arcs of radius 4cm which intersects each other at point A.

Step 3: Join AB and AC.

Step 4: Draw the right bisector of BC and AC intersecting each other at point O.

Step 5: Join OA, OB and OC.

Step 6: With center as O, and radius equal to OB or OC or OA, draw a circle which passes through points A, B and C.

Hence the required circumcircle of triangle ABC is given below.