Calculate the area of the shaded region in each figure. Use 3.14 and round to the nearest tenth, if necessary.

Given:

A larger circle consisting of two circles with radii of 4 cm and 8 cm each.

To find:

The area of the shaded region.

Solution:

The centers of the circles with radii 4 cm and 8 cm lie on the same line as the center of the larger circle.

So the diameter of the outer circle cm.

If the diameter is 24 cm, the radius is cm.

The area of the shaded region is obtained by subtracting the areas of the two inner circles from the outer circle.

The area of a circle

The area of the circle with radius 12 cm square cm.

The area of the circle with radius 8 cm square cm.

The area of the circle with radius 4 cm square cm.

The area of the shaded region square cm.

Rounding this off to the nearest tenth, we get the area of the shaded region as 201 square cm.