: Length of a circle and area of a disk.

While direct download links for the latest edition of the workbook can be elusive due to copyright, the following related digital resources are available:

: Equation of a circle and equation of a line.

The search for the 9th-grade geometry workbook (рабочая тетрадь) by (А.В. Фарков) shows that it is primarily designed to accompany the standard geometry textbook by Atanasyan and others. Available Resources for A.V. Farkov (Geometry, Grade 9)

If you are using the workbook for self-study, these are the core sections typically covered in a 9th-grade geometry program:

: Sine, cosine, tangent, and cotangent of an acute angle in a right triangle.