### Theory:

Working rule to construct a tangent to a circle (Using the centre):
Given the radius of a circle, let us learn how to construct a tangent to the circle using its centre.
Example:
Draw a circle of radius $$3$$ $$cm$$. Take a point $$P$$ on this circle and draw a tangent at $$P$$.

Rough Sketch:

Construction:

Step $$1$$: Draw a circle with centre at $$O$$ of radius $$3$$ $$cm$$.

Step $$2$$: Take a point $$P$$ on the circle and join $$OP$$.

Step $$3$$: Draw perpendicular line $$TT'$$ to $$OP$$ which passes through $$P$$.

Step $$4$$: $$TT'$$ is the required tangent.