Find the area of the shaded portion intersecting between the two circles. show all work for full credit.

Solution:

Join other end of chord from the center of two circles.

As these two circles are concentric circles .

And the triangles are equilateral triangle.

Area of sector

=

Area of equilateral triangle having side 4 cm= =

Area of region I = Area of sector - Area of equilateral triangle having side 4 cm

                          = cm²

Area of colored region = 2 × Area of region I

                                       = 2 × 1.461

                                        = 2.922 cm² (Approx)