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Question
If the numerical value of the area of a circle is equal to the numerical value of its circumference , find its radius.
Solution
Given that area of the circle = circumference
\[\pi r^2 = 2\pi r\]
\[ \Rightarrow \pi r^2 - 2\pi r = 0\]
\[ \Rightarrow \pi r\left( r - 2 \right) = 0\]
\[ \Rightarrow r = 0 or r = 2\]
Since radius cannot be equal to 0 so, r = 2
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