ANSWER
The circumference doubles
EXPLANATION
Let the radius of the circle be r and the circumference be C.
The circumference of a circle is given as:
[tex]C=2\pi r[/tex]If the radius is doubled, the radius becomes:
[tex]2r[/tex]The circumference now becomes:
[tex]\begin{gathered} C^{\prime}=2\pi\cdot(2r) \\ C^{\prime}=2\cdot(2\pi\cdot r) \\ C^{\prime}=2\cdot(2\pi r) \\ C^{\prime}=2C \end{gathered}[/tex]Therefore, the circumference doubles when the radius is doubled.
