Steps of Construction:
Step 1: Draw a circle with O as center and radius 3 cm.
Step 2: Mark a point P outside the circle such that OP = 7cm.
Step 3: Join OP. Draw the perpendicular bisector XY of OP. cutting OP at Q.
Step 4: Draw a circle with Q as center and radius PQ (or OQ), to intersect the given circle at the points T and T’.
Step 5: Join PT and PT’.

Here, PT and PT’ are the required tangents.
PT = PT ' = 6.3cm (Approx.)