Step-by-step explanation:
The circumference of a circle is equivalent to its outer boundary. The circumference of a circle is given by :
[tex]C=2\pi r[/tex].............(1)
r is the radius of circle
It is clear from equation (1) that the circumference of circle is directly proportional to its radius. For example, if the radius of circle is 2 cm, its circumference would be [tex]4\pi[/tex].
On increasing the radius i.e. 4 cm, circumference becomes [tex]8\pi[/tex].
The relationship between the area and the radius of circle is given by :
[tex]A=\pi r^2[/tex]
r is the radius of circle
Hence, this is the required solution.