Area between a square and its circumscribed or inscribed circle

This type of question, asked 2 times: CDS 1 2018, CDS 2 2018. All 2 questions below, oldest first.

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Question 1
CDS 1 2018
95 $What is the area of the region bounded internally by a square of side of length 'a' and externally by a circle passing through the four corners of the square ?$
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Question 2
CDS 2 2018
90 $The area of the region bounded externally by a square of side 2a cm and internally by the circle touching the four sides of the square is$
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