Draw a circle of radius 4.2cm

Hint: Make use of the definition of the radius of the circle which says that radius is the line segment from the centre to its perimeter

Complete step by step answer:
First take a fixed point ‘O’ on the plane as a center of the circle.
Then take the radius (distance) of 4.2cm and name that point P as shown in figure.
Now by taking this line as reference draw a circle with radius OA of as shown below.

As it circle all the points will be at the same distance from point O which is 4.2cm

Note: Be specific with the radius to draw a proper circle.If the length of a diameter of a circle is given,make sure you convert the diameter to radius and then construct a circle.