Observe the diagram.

Central angle are and .

Radius of the smaller circle is cm.

Convert central angle degree measure to radians.

.

Find area of a sector of the smaller circle.

Area of sector : .

Substitute and in .

Area of shaded region of smaller circle is .

Convert central angle degree measure to radians.

.

Find area of a sector of the smaller circle.

Area of sector : .

Substitute and in .

Area of smaller circle is .

Find area of a sector of the larger circle.

Radius of the smaller circle is cm.

Area of sector : .

Substitute and in .

Area of larger circle is .

Area of shaded region of large circle is .

Area of shaded region of smaller circle is .

Area of shaded region of large circle is .