Three circles of radius 3.5cm are placed in such a way that each circle touches the other two. The area of the portion enclosed by the circles is

required area = (area of an equilateral triangle of side 7 cm)- (3 * area of sector with à = 60 degrees and r = 3.5cm)
$\frac{3}{4}*7*7-3*\frac{22}{7}*3.5*3.5*\frac{60}{360}$ sq cm

= $\frac{3}{4}*49-11*0.5*3.5$ sq cm

= 1.967 sq cm