We know that the area of the circle can be calculated using the formula:

If we know that a certain circle has an area equal to 64π m², we can determine the radius of the circle as follows:
-First, replace the formula with the known area:

-Second, divide both sides of the equation by π:

-Third, apply the square root to both sides of the equal sign to determine the length of the radius:
![\begin{gathered} \sqrt[]{64}=\sqrt[]{r^2} \\ 8=r \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/lxfo9e3v0oao5oa181u1gvvo0fkwfphc68.png)
The radius of the circle is r=8m
The diameter of any circle is twice the radius, so that:
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