All seven smaller circles are tangent to each other, and the larger circle is tangent to the six outer smaller circles. the radius of each of the smaller circles is 3 cm. In cm^2, the sum of the areas marked "a" is.
Radius of large circle = 9......area = pi * 9^2 = 81 pi cm^2
Total area of smaller circles= (7) pi (3)^2 = 63 pi cm^2
Total area of a's = 81 pi - 63pi = 18pi cm^2
+39 
