Steps of construction
1. Draw a circle of radius 4 cm. Let centre of this circle is O.
2. Take a point M at 6cm away from the radius.
3. Join OM and bisect it. Now, with M and O as centres and with radius more than half of draw two arcs on the either sides of the line OM. Let the arc meet at A and B,just that, M1 be mid-point of OM.
4. Taking M1 as centre and M1O as radius draw a circle to intersect circle with radius 4 and centre O at two points P and Q.
5. Join PM and QM. PM and QM are the required tangents from M to circle with centre O and radius 4.