This figure shows five shaded circles within a circle of radius 7 units. The four small congruent shaded circles are tangent to the outer circle and to the large shaded circle. The radius of each of the smaller shaded circles is 1/5 the radius of the large shaded circle. What fraction of the largest circle's area is shaded? Express your answer as a common fraction.

FBIOPENUP Jan 12, 2020