7. In Fig, ABCD is a square of side 14 cm. With centres A, B, C and D, four circles are drawn such that each circle touch externally two of the remaining three circles. Find the area of the shaded region.
It is clear from the figure that area of all sectors are equal (due to symmetry).
Also, the angle of sector is 90o and radius is 7 cm.
Thus area of sector is :-
or
And, the area of square is :
Hence area of shaded region is :