### Theory:

Construction of a circle:

To construct a circle, we should make a note of the radius.

Radius is the only component required to construct a circle.

A compass is used to construct a circle.

Now, let us learn to construct a circle step-by-step.

Construct a circle with $$3cm$$ as radius.

Step $$1$$: Mark the fixed point as '$$O$$'.

Step $$2$$: Draw a line segment of $$3cm$$ from '$$O$$'. Mark the other end of the line segment as '$$A$$'.

Step $$3$$: With '$$O$$' as centre, place the pointy end on the centre, and rotate the compass firmly from '$$A$$' until the circle is achieved.

Practical construction is as follows:

Construction of two circles from the same centre:

Similar to the steps of construction discussed above, two or more circles can also be constructed from the same centre.

In this case, two or more radii will be needed.

Step $$1$$: Mark the fixed point as '$$O$$'.

Step $$2$$: Draw a line segment of $$3cm$$ from '$$O$$' using a ruler. Mark the other end of the line segment as '$$A$$'.

Step $$3$$: With '$$O$$' as centre, rotate the compass firmly from '$$A$$' until the inner circle is achieved.

Step $$4$$: Draw a line segment of $$7cm$$ from '$$O$$'. Mark the other end of the line segment as '$$B$$'.

Step $$5$$: With '$$O$$' as centre, rotate the compass firmly from '$$B$$' until the outer circle is achieved.

The resultant figure will look like this:

Here, $$OA = r_1 = 3 cm$$

Similarly, $$OB = r_2 = 7 cm$$