Hello, LydiaK67!

The given chord length is tangent to the inner circle.

What is the area of the annulus?Code:* * * * * * x C x * A o - - - - * o * - - - - o B * | * * * * | * * * r| *R * * | * * * | * * * - - * - - - - o - - - - * - - * O

is a chord of circle with radius

It is tangent to the inner circle of radius at

. .

The area of the annulus is: . .[1]

In right triangle .[2]

Substitute [2] into [1]: .