Solution:
Given that, three circles are in such a way that each of them touches the other two.
Now, we join centre of all three circles to each other by a line segment. Since, radius of each circle is 3.5 cm.
So; AB = 2 x Radius of circle
= 2 x 3.5 = 7 cm.
⇒ AC = BC = AB = 7cm
which shows that, ΔABC is an equilateral triangle with side 7 cm.
We know that, each angle between two adjacent sides of an equilateral triangle is 60°
∴ Area of sector with angle ∠A = 60°.

Hence, the required area enclosed between these circles is 1.967 cm2 (approx).