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Haha... in case you are wondering if the area of the circle in the centre is indeed the size of “1 leaf” shape, the answer is they are not exactly the same. They are just pretty close.
Here’s a proof that shows the leaf is 0.57R2, whereas the circle in the centre is 0.54R2.
In any case, to solve the original question, there is no need to prove that.
Given in the question that the centre circle is 1/5 the total shaded area,
we can infer that the circle has the same area as 1 leaf.